Integrated automatic blood processing unit

ABSTRACT

A system for automatically processing blood components is described. The system includes a console, which contains all motors, pumps, sensors, valves and control circuitry, and a unique disposable set that includes a cassette supporting a centrifuge with an improved design, pump interfaces with an improved design, component and solution bags, and tubing. Various processes are implemented using a specific disposable set for each process which allows automatic identification of the process to be performed the console.

RELATED APPLICATIONS

This application claims the benefit of priority under 35 U.S.C. § 119 ofprovisional U.S. patent application Ser. No. 60/374,141, filed Apr. 19,2002, entitled “Integrated Blood Collection and Processing Unit,” thecontents of which are hereby incorporated by reference in theirentirety. This application also claims the benefit of priority under 35U.S.C. § 120 as a continuation-in-part of U.S. patent application Ser.No. 10/179,920, filed Jun. 24, 2002, entitled “Integrated AutomaticBlood Collection and Processing Unit,” the contents of which are herebyincorporated by reference in their entirety.

FIELD OF THE INVENTION

This invention relates generally to devices and methods for theautomated processing of blood or blood components already collected froma donor or patient.

BACKGROUND OF THE INVENTION

Conventional methods and equipment for preserving red blood cells (RBCs)in the frozen state have been available for many years. The U.S.military has stockpiled several thousand units of frozen group O RBCsfor emergency use and may expand these reserves. The civilian blood bankuses for frozen blood include the long-term storage of rare blood typesand the storage of RBCs by donors for anticipated future electivesurgery. Current standard methods for preservation of RBCs byglycerolizing and deglycerolizing are in use by the military andcivilian blood banks (e.g., the American Red Cross and the Naval BloodResearch Laboratory Standard Operating Procedures).

In general, the steps involved in the conventionalglycerolization/deglycerolization process are as follows: (1) wholeblood collection from a donor (e.g., using an anticoagulant); (2)preparation of RBCs from whole blood by removal of plasma (RBCs may beseparated, concentrated and stored in additive solution such as AS-1 orAS-3); (3) addition of glycerol cryopreservative to the RBCs prior tofreezing; (4) freezing of the glycerolized RBCs for long-term storage(up to about 10 years); and (5) thawing and deglycerolizing of the RBCs(up to about 24 hours of refrigerated storage after deglycerolization,and before centrifugation and administration).

At present, RBCs are glycerolized using a manual procedure involving abag shaker, centrifuge and plasma extractor (see, e.g., the American RedCross and the Naval Blood Research Laboratory Standard OperatingProcedures). To deglycerolize RBCs, a manual procedure is also used(see, e.g., the Naval Blood Research Laboratory Standard OperatingProcedures) involving a centrifugal cell washer (e.g., Model 115;available from Haemonetics Corp., Braintree, Mass.). The Haemoneticssystem requires one, nearly full-time user to produce about one unit perhour of deglycerolized RBCs. The Haemonetics centrifugal system is notregarded as closed and sterile because it has a rotating centrifuge bowlseal that is open to room air. Therefore, the deglycerolized RBC productfrom this system must be used within 24 hours or discarded. Anadditional centrifugation step may be required just before RBCadministration to a patient to concentrate the RBCs and remove freeplasma hemoglobin.

There is a need in the art for a device that can provide automatic,rapid, sterile, low-cost glycerolization and deglycerolization andlong-term storage of deglycerolized RBCs for both military andcommercial applications. Such a device would greatly increase thepracticality and usefulness of frozen RBCs.

Additionally, current methods for intra-operative autotransfusionutilize a centrifuge to process blood in batches. The methods andapplications involve processes which are automatic (e.g., the processingof a full centrifuge bowl), while other processes are manual (e.g., thefilling of the bowl and the processing of a less than full bowl).Additionally, the processing parameters for a partially-full centrifugebowl must be manually set if substantial saline dilution and inadequatewaste removal are to be avoided. Conventional, disposableautotransfusion sets are also quite expensive, since most currentsystems use batch processing of blood in relatively large centrifugebowls. System set-up is also burdensome, and takes about five minutes.Finally, a trained perfusionist is usually required to operate aconventional autotransfusion system in open heart surgery, when aheart-lung bypass is being used. A technician operates the system forvascular surgery or orthopedic surgery, also adding to the cost of theprocedure.

There is therefore a need in the art for a fully automatic, safe, easyto set up and use intra-operative autotransfusion system. Such anapparatus may allow a nurse or anesthesiologist to set up and monitorthe system operation during use, saving substantial time and cost.

SUMMARY OF THE INVENTION

The present invention includes a console or electromechanical instrumentthat may be used to perform several different blood processingprocedures. The console is a small, compact apparatus that has thevarious actuation pumps, valves, pressure-sensing transducers,ultrasonic detectors and other devices needed to implement the processusing a closed, sterile disposable set. The invention further includesdifferent disposable sets for each process that is specifically designedto implement that process and to contain all associated blood andfluids. As many functions and devices as possible are placed in theconsole, allowing simplification and reduction in size of the disposableset.

The disposable system includes a cassette to integrate, locate, andsupport all disposable set components that interact with the consoleactuation and sensing components. The disposable set components interactautomatically with their interactive console components withoutsignificant influence by or dependence on the user.

The console uses microprocessor-based electronics and software to selectand control a variety of different processes. The console may identifythe cassette installed in it by reading a bar code on the cassette. Themicroprocessor may then initiate the process appropriate for thatcassette, with user verification. Automated data collection by theconsole plus bar code scanning by the user eliminates manual entries andallows error-free data to be provided to a blood center computer.

Other features of the invention include a low-cost manifold as part ofthe disposable set that contains the actuation and sensing components,and a simple, low-cost, continuous-flow centrifuge assembly with uniquefeatures that increase its efficiency. Additionally, in particularembodiments of the present invention, additional components such asoptical sensors, a free plasma hemoglobin sensor and a recirculation bagshaker may be included to implement or enhance the function of thepresent invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a console, in accordance with anembodiment of the present invention.

FIG. 2 is a perspective view of a console with the door open, inaccordance with an embodiment of the present invention.

FIG. 3 is a perspective view of a console from the rear showing aninterior of the open console door, in accordance with an embodiment ofthe present invention.

FIG. 4 is a cutaway view of a valve plate assembly, in accordance withan embodiment of the present invention.

FIG. 5 depicts a positive pressure sensing transducer and associatedpressure component, in accordance with an embodiment of the presentinvention.

FIG. 6 depicts a negative pressure sensing transducer and associatedpressure component, in accordance with an embodiment of the presentinvention.

FIG. 7 depicts an alternate embodiment for a negative pressuretransducer and associated pressure component, in accordance with anembodiment of the present invention.

FIG. 8 depicts a detailed view of a valve actuator and valve component,in accordance with an embodiment of the present invention.

FIGS. 9A and 9B are views of a door showing the attachment of rotors, inaccordance with an embodiment of the present invention.

FIGS. 10A and 10B are views of pump rotors, manifold pump tubing androtor tracks, in accordance with an embodiment of the present invention.

FIG. 11 is a cutaway of electric motors and rotors, in accordance withan embodiment of the present invention.

FIGS. 12A and 12B depict a drive cup, in accordance with an embodimentof the present invention.

FIG. 13 depicts alternative features for a drive cup, in accordance withan embodiment of the present invention.

FIG. 14 is a first view of a disposable set, in accordance with anembodiment of the present invention.

FIG. 15 is a second view of a disposable set, in accordance with anembodiment of the present invention.

FIG. 16 is a conceptual view of a cassette, in accordance with anembodiment of the present invention.

FIG. 17 is a detailed view of a cassette, in accordance with anembodiment of the present invention.

FIG. 18 is a view of a console with a cassette mounted therein, inaccordance with an embodiment of the present invention.

FIG. 19 is a detailed schematic of a manifold portion of a cassette, inaccordance with an embodiment of the present invention.

FIG. 20 is a cutaway view of ultrasonic sensors, in accordance with anembodiment of the present invention.

FIGS. 21A and 21B depict a conceptual design and operation of acontinuous flow centrifuge that uses a face seal, in accordance with anembodiment of the present invention.

FIG. 22 depicts a detailed design of a continuous flow centrifuge thatuses a face seal, in accordance with an embodiment of the presentinvention.

FIG. 23 depicts a continuous flow centrifuge that uses a face seal asmounted for operation in a centrifuge cup in a console, in accordancewith an embodiment of the present invention.

FIG. 24 depicts a detail of a housing for the centrifuge, in accordancewith an embodiment of the present invention.

FIG. 25 depicts a face seal with three fluid paths, in accordance withan embodiment of the present invention.

FIG. 26 depicts a face seal with four fluid paths, in accordance with anembodiment of the present invention.

FIG. 27 is a conceptual representation of an umbilical or skipropedesign for a continuous flow centrifuge, in accordance with anembodiment of the present invention.

FIGS. 28A and 28B are views of a continuous centrifuge disk with anumbilical with a cassette mounted to the front panel of a console, inaccordance with an embodiment of the present invention.

FIG. 29 is a view of drive mechanisms for an umbilical continuous flowcentrifuge, in accordance with an embodiment of the present invention.

FIGS. 30A and 30B are cutaway views of an umbilical continuous flowcentrifuge, in accordance with an embodiment of the present invention.

FIG. 31 is a view of an umbilical continuous flow centrifuge mounted toa console front panel, in accordance with an embodiment of the presentinvention.

FIG. 32 is a conceptual representation of an alternative umbilicaldesign, in accordance with an embodiment of the present invention.

FIG. 33 is a conceptual representation of a gear and bearing arrangementof an embodiment of the umbilical continuous flow centrifuge depicted inFIG. 32, in accordance with an embodiment of the present invention.

FIG. 34 depicts a conceptual design for a continuous centrifuge diskseparation channel, in accordance with an embodiment of the presentinvention.

FIG. 35 depicts, conceptually, a detail of a separation channel, inaccordance with an embodiment of the present invention.

FIG. 36 depicts a detail of a continuous flow centrifuge separationchannel with two plasma pickup ports, in accordance with an embodimentof the present invention.

FIG. 37 depicts a continuous centrifuge disk with a first design for aseparation channel, in accordance with an embodiment of the presentinvention.

FIGS. 38A and 38B depict a continuous centrifuge disk with a seconddesign for a separation channel, in accordance with an embodiment of thepresent invention.

FIG. 39 depicts a conceptual detail for a third design for a separationchannel, in accordance with an embodiment of the present invention.

FIGS. 40A and 40B depict a design for a plasma port that includes a ballvalve in a first position, in accordance with an embodiment of thepresent invention.

FIGS. 41A and 41B depict a design for a plasma port that includes a ballvalve in a second position, in accordance with an embodiment of thepresent invention.

FIG. 42 depicts a continuous centrifuge disk with a fourth design for aseparation channel, in accordance with an embodiment of the presentinvention.

FIG. 43 depicts a continuous centrifuge disk with a fifth design for aseparation channel, in accordance with an embodiment of the presentinvention.

FIG. 44 depicts a continuous centrifuge disk with a sixth design for aseparation channel, in accordance with an embodiment of the presentinvention.

FIGS. 45A and 45B depict a continuous centrifuge disk with a seventhdesign for a separation channel, in accordance with an embodiment of thepresent invention.

FIG. 46 depicts a conceptual representation of a channel design, inaccordance with an embodiment of the present invention.

FIGS. 47A and 47B depict an eighth separation channel design, inaccordance with an embodiment of the present invention.

FIGS. 48A and 48B depict a ninth separation channel design, inaccordance with an embodiment of the present invention.

FIG. 49 depicts a tenth separation channel design, in accordance with anembodiment of the present invention.

FIG. 50 is a cutaway view of a light detector for use in determining theRBC/plasma interface in a continuous flow centrifuge, in accordance withan embodiment of the present invention.

FIG. 51 is a schematic of a system to implement a glycerolizationprocess, in accordance with an embodiment of the present invention.

FIG. 52 is a schematic of a system to implement a glycerolizationprocess, in accordance with an embodiment of the present invention.

FIG. 53 is a schematic of a system to implement a deglycerolizationprocess, in accordance with an embodiment of the present invention.

FIG. 54 is a schematic of a system to implement a deglycerolizationprocess, in accordance with an embodiment of the present invention.

FIG. 55 is a schematic of a system to implement a deglycerolizationprocess, in accordance with an embodiment of the present invention.

FIG. 56 is a schematic of a system to implement a deglycerolizationprocess, in accordance with an embodiment of the present invention.

FIG. 57 is a schematic of a system to implement a deglycerolizationprocess, in accordance with an embodiment of the present invention.

FIG. 58 is a schematic of a system to implement a deglycerolizationprocess, in accordance with an embodiment of the present invention.

FIG. 59 is a schematic of a system to implement an intra-operativeautotransfusion process, in accordance with an embodiment of the presentinvention.

FIG. 60 is a schematic of a system to implement a process for thepreparation of a therapeutic dose of leukoreduced platelets from pooledbuffy coats, in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Console

With reference to FIGS. 1–3, the system includes a console 100, having aconsole body 110 enclosing electronic, electro-mechanical and mechanicalcomponents. A console door 130 is connected to the front panel 120 ofthe console body 110 using a hinge 140 along the front horizontal bottomof the front panel 120. The door 130 may also include a door plunger 295(shown in FIGS. 21B and 23), which interacts with certain designs of acentrifuge element on the disposable set as further described below. Alatch 145 secures and positions the console door to the front panel 120at the top and may be operated through the use of a handle 150 on thedoor. Hangers 310 on the outside of the console 100 may be used to holdsolution and blood product bags 580, 590 (which are part of a disposableset 480 illustratively depicted in FIGS. 15 and 16). Four roller pumps160 and their drive mechanisms are shown as mounted on the inside of thedoor 130; although different numbers of roller pumps 160 and their drivemechanisms may be included in alternate embodiments of the presentinvention. Power may be provided to the system from alternating currentsources and/or direct current sources such as batteries (not shown) toallow for portability.

With reference to FIGS. 2, 4, 5 and 6 the substantially vertical frontpanel 120 of the console locates and positions roller pump tracks 170,pressure transducers 190, valves (which may be solenoid valve actuators210, as shown), a centrifuge drive cup 220, ultrasonic sensors 240 andpins 230 (from which to hang a disposable cassette 490, which is furtherdescribed below in connection with FIGS. 15 and 16). The valve actuators210 and positive pressure transducers 193, 195, and negative pressuretransducer 200 are mounted to a valve plate 280 that is part of andattached to the console front panel 120. Valve actuators 210, includinga washer 320 and seal 330, are mounted on the valve plate 280 and frontpanel 120 so as to be opposite valve components 520 in the cassette 490of the disposable set 480.

Placement of the roller pump and drive mechanisms on the door withvalves and sensors in the console body may allow for a more compactcassette design as the roller pump and drive mechanisms do not competefor space on the console front panel with the valves, sensors and otherelements. However, as alternatives to the design shown and described,the roller pumps and drive mechanisms may be placed in the console onthe front panel 120, and/or the valves 210 and pressure transducers 190and/or other components may be placed on the interior of the door, withappropriate modifications to the design of the disposable set.

Each valve actuator 210, shown in detail in FIG. 8, has asolenoid-operated plunger that moves the valve diaphragm 530 of adisposable valve component 520 to open or occlude a fluid path orifice.The valve actuator 210 shown may be biased closed by a spring (notshown). A low power level would be needed to keep the valve in an openposition, as shown in FIG. 6. The spring-loaded feature is a fail-safeadvantage; ensuring that no fluid flow can occur with a system or powerfailure. The motion of the plunger may be independently monitored with aHall effect or optical sensor (not shown) to provide confirmation ofproper valve function and a warning of solenoid failure.

With reference to FIGS. 4–7 the pressure transducers 190, both positiveand negative 193, 195, 200, may be flat-faced standard devices thatcouple directly to the pressure diaphragm 540 on pressure measurementcomponents 545 in the cassette. Negative pressure is sensed as shown inFIG. 10, as the diaphragm 540 is deformed. Positive pressure is sensedas shown in FIG. 11, when the diaphragm 540 is not deformed.

The console front panel also includes ultrasonic sensors withinterfacing fingers mounted in the door. The operation of these devicesis described below in connection with the cassette.

With reference to FIGS. 9–11, the roller pump and drive mechanism 160include a number of components. Two roller pump rotors 350 are mountedon concentric shafts 360, supported by bearings 420 within bearingblocks 430, and driven, through belt drives 370, including sprockets380, from two motors 390, which may be brushless D.C. motors, on amounting bracket 440 attached to the door 130. The rotors 350 may bedesigned to be easily removed from the shafts 360 for cleaning by usinga mechanism such as a spring-loaded key 400 that is manually activated.Two such assemblies are mounted in the console door. Four independenttracks 170 are mounted to the console front panel 120. These tracks 170are spring-loaded 180 against roller pump tubing sections 690 which arelocated between the tracks 170 and rotors 350 when the cassette ismounted on the console 100. In alternate embodiments, different numbersof these components may be included in the system of the presentinvention.

Each rotor has six to eight rollers 410 equally spaced on its periphery.The small spacing between rollers 410 and the relatively large rotordiameter allow a short track length and short tubing segment on thedisposable. This tubing segment is deformed into a short, shallow arc bythe rotor and track. As the rotor turns during operation of the system,the rollers 410 force the movement of any liquid, blood, for example,contained in the tubing. Short pump tube segments are desirable in orderto minimize overall manifold 510 and cassette size and cost.Additionally, the combination of features allows for a cassette designthat automatically places the appropriate pump tube segments in operableconnection with the correct pumps and tracks when the cassette ismounted on the front panel and the door is close, thus eliminating theneed for an operator to make such connections and the potential forerror.

With reference to FIGS. 2, 12, 13 and 23, a centrifuge drive cup 220 islocated in the console front panel 120 in order to accept and support acontinuous flow centrifuge (CFC) disk 930 on the disposable, which isfurther described below. The drive cup 220 may have a shield 450 aroundit inside the console 100. The drive cup 220 is supported on acentrifuge drive shaft 460, which has bearings 448 spaced at each end,with a stationary housing 449 and motor mount 447 supporting thesebearings 448. A shield (not shown) may optionally be attached to thatportion of the back of the front panel 120 to which the stationaryhousing 449 is bolted. This achieves a leak-tight assembly preventingfluids from entering the console 100. As one alternative, the drive cup220 may optionally include locking ears 222 and associated stop pins 223for locking the centrifuge into the cup 220. As another alternativeelement in the design, pins 225 may extend from the bottom of the cup tointerface with holes 226 in the centrifuge so as to hold the centrifuge515 in place in the cup and correctly orient the cup and CFC disk 930.As yet another alternative, a slot 227 on one side of the drive cupaccepts a tab 228 on the centrifuge, to further hold the centrifuge inplace in the cup during operation and orient the centrifuge. The shaft460 is driven by a brushless D.C. motor (not shown), preferably with aposition encoder, located in the console 100. The motor driveelectronics (not shown), mounted in the console 100, may use thisencoder to achieve the necessary very smooth, vibration-free,constant-speed rotation of the centrifuge and also allows for the pins225, slot 227 or other orientation element to be properly positionedwhen the cup is stopped so as to allow for proper placement of thecentrifuge 515 and the CFC disk 930.

With reference to FIG. 28B, to interface with certain centrifuge designsincluding an umbilical 1670, the cup includes dual gears 1750 to drivethe centrifuge disk while the umbilical 1670 is rotated by the cup 1761.In another alternative, concentric cups may be used, the first cup 1761for rotating the umbilical, and within that cup 1761 a second cup 1762for rotating the CFC disk 930 at twice the rotational velocity of thefirst cup 1761. The second cup 1762 includes a slot to allow theumbilical to be properly placed in the first cup. These embodiments arefurther described in detail below in connection with the umbilicaldesign.

A user interface 250 is located on the outside of the top of the console100. Preferably, the interface provides sealed push-button or diaphragmswitch controls for implementing user control of the specific functionsof the processes implemented by the console 100 to a limited andwell-defined extent. The user interface 250 includes a display 260,which may be an alphanumeric illuminated monitor, for displaying thestate of the process, for display and selection of process parameters,and for warnings or alarm conditions. The interface may include a donorline pressure indicator 270.

A bar code reader 275 may be provided in order to take bar code datasuch as identifiers, lot numbers and expiration dates from bags, theuser, the donor and other sources. The console 100 provides date, time,and process and blood product information. All process and system data,process parameters, warnings, failures and a process validation may thusbe automatically provided to a central blood bank computer.

All processes within the system are controlled by electronic controls(not shown) contained within the console 100 in a conventional mannerutilizing a microprocessor-based controller with a watchdogmicroprocessor, or dual microprocessors, that meet medical deviceelectronic system requirements. Electronic PC boards or similarstructures, shown for example, at 340, provide electronic interfaces tovarious motors, actuators, transducers, and sensors. Although not shown,it will be understood that all operations of components are controlledand/or monitored by the microprocessor or other controller utilizingstandard techniques known in the art, in response to inputs from thesensors, such as the pressure transducers, and to set process proceduresprogrammed into software, stored in a ROM or other storage device, whichis used to implement the process identified using a bar code 276 orother identifier on the cassette 490 that may be read by the bar codereader 275 or the like mounted in the console. It will be understoodthat all components will be electronically coupled to such controllervia control circuits such as the transducer printed circuit board.Control software to control the microprocessor may be written in C+ oranother suitable programming language, and should follow FDA and ISOguidelines for medical device software. As an alternative to amicroprocessor and control software instructions, a state machine, whichcould be implemented using an FPGA, could be used.

Disposable Set

The disposable sets 480 for processes implemented by the system haveseveral components as well as the overall design approach in common.This overall design is illustratively depicted in FIGS. 14 and 15 (withrespect to a related system of blood collection and processing) with thestructure of the cassette shown conceptually in FIGS. 16 and 17. Thedisposable set 480 consists of a cassette 490, including a manifold 510,a CFC 515 and a cassette frame 500 that supports the manifold 510 andthe CFC 515. The frame may be formed of injection-molded plasticdisposable component or similar material with sufficient rigidity tosupport the manifold 510 and CFC 515, and to allow the valve and sensorcomponents 525 to be located opposite the actuators and sensors mountedon the console front panel 120 and console door 130. The manifold, frameand portions of the CFC are preferably made of clear plastic so as toallow for the use of optical sensors mounted in the console, as furtherdescribed below. The cassette also has a bar code 276 that may be readby the bar code reader 275 in the console 100. This providesidentification to the console 100 of the process to be implemented. Itmay also provide cassette calibration valves to allow for more efficientpump operation, cassette lot number and expiration date.

The disposable set 480 also includes various components 570 that areattached to the manifold 510 by tubing 550. These components 570 mayinclude one or more solution bags or bottles, such as a glycerolizingsolution bag, saline solution bag or a platelet additive solution (PAS)bag, or a glycerol bottle; blood product bags, such as a bag of packedRBCs in storage solution, a frozen red cell product bag, a glycerolizedRBC bag, a deglycerolized RBC bag, a platelet product bag, buffy coatproduct bags, a white cell product bag or a washed RBC bag; arecirculation bag; a satellite bag; and a waste bag. Variouscombinations of these bags and bottles may be utilized, according todifferent embodiments of the present invention.

The cassette 490 may be mounted on the vertical front panel 120 of theconsole, as shown in FIG. 18. The cassette 490 is held by the uservertically and is lowered into the space between the open door and thevertical console front panel 120. It is lowered until the support andalignment holes 680 in the top of the cassette 490 as shown in FIG. 18are opposite the horizontal locating pins 230 on the front panel 120.The holes 680 and pins 230 may be placed strategically to permit onlyone possible placement of the cassette 490 within the console 100. Withreference to FIGS. 35A and B, the cassette 490 is then pushedhorizontally toward the front panel 120. The CFC 515 will first engageand slip easily into its console drive cup 220 mechanism. In a rotatingcup design, pins 225 in the cup, and/or slots if an umbilical design isused, will have been properly oriented using the position locator in thedrive motor. Then the locating pins 230 on the console front panel 120will engage the support and alignment holes 680 in the cassette 490. Theprocess of mounting the cassette 490 takes no appreciable force and iscompleted when the cassette 490 is mounted on the pins 230 and iscontacting the console front panel components. Then the console door isclosed and latched, securing the cassette 490 between the door and theconsole front panel 120. This cassette mounting process takes a fewseconds. Then components 570, such as solution bags and blood productbags, are hung and/or connected, and the system is ready for use.

The cassette 490 is hung vertically on the console front panel 120 toallow easy, direct, close visual observation of mounting of cassette 490to the console 100. Vertically-mounted cassettes may be easier to insertinto the console 100 than horizontally-mounted cassettes. Verticalmounting also allows for a vertical door design that does not requirelifting the entire weight of the door as with a horizontal door and avertical front panel 120, which may be more easily cleaned than ahorizontal front panel. Additionally, substantial vertical positioningof the cassette may allow gravity to aid in separating air from liquidin the disposable set 480 components 570; air removal, including airremoval during the initial priming or filling of the centrifuge (usuallyincluding a slow rotation or clocking of the rotor) may be easier sincethe centrifuge can be positioned to allow air to move upward alongvertical fluid pathways. Furthermore, as a safety feature, fluid leaksmay be seen more easily and quickly when they occur since the fluid isnot contained on a horizontal surface but flows downwards along verticalsurfaces for collection at the bottom of the cassette 490. Finally, thevertically-mounted cassette 490 allows for a substantially horizontalrotor on the centrifuge drive which permits fluids to drain from and notaccumulate in the drive and allows air to be more easily removed.

The manifold 510, which may be bonded or ultrasonically welded to thecassette frame 500, is shown in more detail in FIG. 19, and incorporatesseveral components, including roller pump tubing sections 690 for liquidflow control, fluid flow pathways to the sensor and valve actuationcomponents 546, 520, which are more specifically identified below in thediscussion of the various system procedures; valve diaphragm 530components to turn on or off fluid flow in selected fluid pathways 750;and pressure diaphragm 540 components to measure selected fluid pathway750 pressures.

The manifold 510 includes molded-in fluid pathways 760 and may includeinterfaces for valves and sensors. In the embodiment illustrativelydepicted in FIGS. 18 and 19, four roller pump tubes 690 are connected tovarious fluid pathways 760. The fluid pathways 760 end in tubingreceptacles 934–939 and 941–950 for receiving tubing 550 that attachesselected components 570 appropriate for the process the cassette 490 isintended to perform. It will be appreciated by those of ordinary skillin the art that a primary feature of the system is flexibility, in thatit may perform different process by utilizing different cassettes andsoftware. For this reason, not all of the fluid pathways and/or rollerpump tubes would be used in every process, and, depending on theprocess, some could be selectively eliminated without affecting theperformance of the cassette. Furthermore, the exact position of thevarious tubing, valves and pressure sensors could be altered, providingthe associated elements of the console 100 were modified accordingly,without affecting the basic concepts of the manifold design. For ease ofexplanation of the structure of the manifold 510, however, the figuresinclude fluid pathways and tubing that would not be used in allprocesses. Additionally, including all possible fluid pathways andtubing for multiple processes could assist in the manufacturing processby allowing for a consistent basic manifold structure that could be usedwith more than one process. Ideally, a single manifold structure couldbe used with all processes.

As depicted in FIGS. 5–8, the manifold 510 consists of three parts: amid-body 780 into which channels, including fluid pathways 760 aremolded from one side; a back cover 790, adjacent to the console frontpanel 120 when in operation, which seals the valves, pressure sensorsand any other component interfaces; and a front cover 800, adjacent tothe console door when in operation, that covers and seals each fluidpathway. The back cover 790 traps the elastomeric valve diaphragms 530and pressure diaphragms 540, which are part of the valve and sensorcomponents 520, 546, and which may be two-part molded to the front cover800 at the location shown at 770, between the front cover 800 and themid-body 780. The elastomeric diaphragms provide the deformable surfacesfor valve and pressure sensor interfaces. It may also be appropriate tomold fluid pathways 760 in both sides of the mid-body, allowing for morechannels and potentially simplified arrangement of elements on thecassette.

The operation of the valve components 520 will now be described. Whenthe cassette 490 is mounted on the front panel 120, the valve diaphragms530 are each located opposite the valve actuators 210, shown assolenoids with plungers 290, secured to the front panel 120. Theelastomeric valve diaphragm 530 is in a normally open position when notdeformed by the plunger 290, and resists deformation by the plunger 290to close the valve. The valve diaphragm 530 also resists negativepressures and does not close when exposed to such pressures within thefluid path. When the console door is closed, the cassette 490 is movedby the door up against the console front panel 120 and the spring-loadedplunger 290 is thereby forced against the diaphragm 530. The valvediaphragms 530 are deformed by the spring-loaded plungers 290 on theconsole 100 to contact and occlude a tubular port 810 molded into themid-body 780 and thereby close a fluid pathway. The tubular port 810 hasa raised annulus 820 around it against which the plunger 290 pushes,creating a seal and closing the port and fluid flow path. When thesolenoid is energized, the plunger 290 pulls away from the manifold 510,allowing the diaphragm 530 to pull away from the port due to itselastomeric bias, and the fluid path is open. With reference to FIGS. 11and 12, the pressure diaphragms 540 contact pressure transducer 190faces to expose the transducer face 830 to the fluid pressure. The frontand back covers 790, 800 are ultrasonically welded to the mid-body 780along each side of each valve, pressure or other components and thefluid pathways 760 to prevent fluid leaks between pathways or to theoutside.

The sensor components 546 will now be described in more detail. Thedesign of the positive pressure components, which are integrated andmolded into the cassette 490, are shown in FIG. 5. A flexibleelastomeric pressure diaphragm 540, of material similar to the valvediaphragm 530, is sealed between the back cover 790 and the mid-body 780of the manifold 510. Fluid pathways 760 bring fluid into and out of themid-body 780 space 781 adjacent to the diaphragm 540. When the consoledoor is closed, the outer surface of the pressure diaphragm 540 contactsthe face of a pressure transducer 191 which is mounted to the consolefront panel 120. The fluid in the fluid pathway 760 exerts pressureacross the highly flexible diaphragm 540 to the transducer face 830. Thetransducer output may be reset to zero every time a new cassette 490 isinstalled and before the process is begun, using ambient air pressureinside the manifold 510.

One possible design of the negative pressure component is shown in FIG.6. It is much like the positive pressure interface design, except aspring 845 causes the piston 840 to exert a fixed force equivalent, inthe example shown, to a pressure of about 250 mm Hg on the diaphragm 540and on the negative pressure transducer or sensor 200. The function ofthe spring-loaded piston 840 is to keep the pressure diaphragm 540 incontact with the sensor face 830 during negative fluid pressures andprovide a fixed pressure offset. Consequently, in the example shown,when the pressure reading is zeroed at ambient pressure before theprocess begins, the transducer in reality is seeing the pressure of thespring-loaded piston 840, but reading zero. Thus, a negative fluidpressure can be measured down to the negative of the fixed forceequivalent, in this case −250 mm Hg, before the pressure diaphragm 540pulls away from the transducer face 830. However, no pressure less thanthe negative value of the equivalent fixed force, or −250 mm Hg in theexample shown, can be read.

An alternative negative pressure design is shown in FIG. 7. In thisdesign, the elastomeric pressure diaphragm 540 has a peripheral sealmember 850 that seals the pressure diaphragm 540 to the console frontpanel 120. Air is trapped in the space 781 between the pressurediaphragm 540 and transducer face 830. This permits positive andnegative pressures to be read by the transducer via the trapped airvolume. This transducer or sensor is also zeroed by ambient pressurebefore the process begins.

With reference to FIG. 19, the four roller pump tubing segments 690 canbe constructed of segments of extruded PVC tubing formulated anddimensioned to have properties optimized for use with the roller pump160. In the embodiment shown, these roller pump tube segments 690 are intwo sets of two; allowing interface with the roller pump rotors mountedin two sets of two on concentric bearings. This design creates a morecompact cassette design. They include four tubing segments 700, 710,720, 730. In each set the tubes are adjacent to one other, parallel, andclosely spaced. This tubing is slightly stretched onto and bonded tobarbed fittings 860 molded to and part of the cassette mid-body 780.

With reference to FIGS. 3 and 10A, the roller pump and drive mechanism160 with motors are located in the console door. The roller pump tubesare unengaged when the console door is open. When the door is closed andlocked in place, the roller pump rotors 350 engage the roller pumptubing 690. The rollers 410 on each rotor compress and occlude thetubing against a curved block or track that is mounted to the consolefront panel 120. No action on the part of the user is needed except toclose the door. This eliminates the manual step of inserting tubing intoeach pump assembly required by many blood processing systems andeliminates the possibility of operator error.

The track may be spring-loaded 180 against the rollers 410 to ensureadequate occlusion while avoiding excessive force. The track 170 ispivoted on a track pivot pin 175 parallel to the console front panel 120at some distance from the center of the track 170. The track is providedwith a stop 177 that limits its motion in the direction of the springforce, which is biased towards the rotors 350. The control of springforce and tubing compression by pump rollers 410 to the lowest levelnecessary to ensure occlusion minimizes hemolysis in this pump design.The roller pump tube segment inside diameter is selected for the flowrates of fluid desired, the degree of “pulsatility” of the fluid thatcan be allowed, and the speed range capability of the pump rotors 350.This inside diameter is controlled precisely, with tolerances preferablyof less than plus or minus 3 mils, in order to achieve accurate flowcontrol in operation as the rotors 350 force the rollers 410 over theroller tubing segments to pump the various liquids through the system.

The manifold 510 also supports tubing 550 that is routed from themanifold 510 to bags and/or other components 570. The tubing 550provides a path for fluids moving to and from components 570. Tubing 550is bonded to or captured onto the frame at the tubing receptacles, asshown in FIG. 19. With reference to FIGS. 14–16, the components 570 varyfor each process, but can include such items as a leukofilter 610 forred cells; bacterial filters 600 for anticoagulant, red cell additive,glycerolizing solution, PAS, glycerol or other solution bags or bottlesattached to the set by the use of spikes 870 or by Luer connectors 880;possible air or bubble traps (not shown); bags for blood products 590,including, for example, red blood cell bags, buffy coat bags, plasmabags, packed RBCs in storage solution, frozen red cell product bags,glycerolized RBCs bag, deglycerolized RBCs bag, platelet product bag,white cell product bags or washed RBCs bags; a recirculation bag; asatellite bag; a waste bag; and other various fittings, elbows,Y-connectors, and manual clamps as appropriate. Some of these components570 may be attached to the cassette frame 500. Preferably, all tubing550 is bonded into selected tubing receptacles 934–939 and 941–950 onone side of the manifold 510, as shown in the embodiment illustrativelydepicted, to simplify and shorten tubing runs to components 570 or bags.The specific components 570 for various processes are indicated in theprocess descriptions and schematics that are described in more detailbelow.

With reference to FIGS. 16, 17, 18 and 20, portions of the tubing 890from the components 570 are bonded or captured to the frame on each sideof access holes 900 in the cassette frame 500 and engage ultrasonicsensors 240 mounted in the console front panel 120. The tubing 550 canbe standard PVC tubing used for fluid flow from the cassette 490 tovarious external components 570, bags, and the like. The access hole inthe cassette frame 500 bridged by the tubing 550 permits the yoke-shapedsensor to surround the tubing segment on three sides. When the cassette490 is hung on the front panel 120, the air detection tubing is adjacentto and partially within the slot 910 in the sensor. When the door 130 isclosed, a finger 920 on the door pushes the tubing into the slot 910 andcompresses it to ensure good contact with the parallel sides of the slot910 achieving good acoustic coupling. An ultrasonic transducer sendsultrasonic waves through the tube across these parallel sides to areceiving transducer on the opposite side of the slot 910. Thedifferences in acoustic properties between liquids, air and air bubblesin liquids are determined by the ultrasonic sensor and its electronics.This is used to monitor air in the system, for ensuring the process isoccurring without air bubbles and for detecting empty liquid-containingbags.

With reference to FIGS. 17 and 18, the CFC 515, including the CFC disk930, is also connected to the manifold 510 by tubing 940. The cassetteframe 500 supports the CFC disk 930 loosely and allows direct, easyinsertion of the centrifuge into the centrifuge drive cup 220simultaneous with hanging the cassette 490 on the console front panel120, without complicating cassette mounting. Details of the CFC 515 arefurther described below.

Continuous Flow Centrifuge

The CFC 515 is “flexibly” supported on the cassette frame 500 such thatit is easily inserted into a centrifuge drive cup 220, 1762 duringcassette installation. This “flexible” support structure is decoupledfrom the disk 930 when the door is closed, permitting the CFC disk 930to rotate freely. The attachment of the CFC disk 930 to the cassetteframe 500 is shown in FIGS. 17 and 18. The CFC disk 930 is attached tothe cassette 490 in such a way that it can readily move approximately±0.040 inch in any direction parallel to the front panel 120 andapproximately 0.1 inch toward the front panel 120. Two pins 960 at 180°from one another on the disk static seal housing 1430 fit loosely in twoyokes 970 that are part of the cassette frame 500. In the embodimentsdepicted, the CFC disk 930 is approximately 6 inches in outside diameterand 1.75 inches thick, although other dimensions are possible.

Two possible approaches to the design of the CFC 515 are describedbelow. In the first approach, with reference to FIGS. 21–24, the CFCapparatus includes several elements that are able to rotate around acentral spin axis 1460. These elements include a housing mounting ring1450, a rotating face seal, a disk cap 1500 and a disk body 1150. Therotating face seal 1480 is supported adjacent to the disk cap 1500,which is mounted on a housing mounting ring 1450 that is rotatablyconnected to rotate around the opening of a bucket-like stationaryhousing 1430. Contained within the housing 1430 and adjacent to therotating face seal 1480 is a stationary face seal 1490, which is bondedto a distributor 1530. The stationary face seal 1490 is slidably mountedin the housing 1430, and is also attached to a spring or otherspring-loading element 1410 mounted at the top of the housing 1430. Withreference to FIG. 24 the housing forms slot or slots 1495 that allowtubing to be connected to the distributor 1530, while permittingmovement of the housing 1430 as described below.

The CFC disk 930 is supported on the cassette 490 but must be free torotate after the cassette 490 is in place, mounted to the console body110 front panel 120, with the console door closed. The console doorclosure is used to disengage the CFC disk 930 from the cassette 490 suchthat the disk 930 can rotate freely and is positioned and supportedcorrectly and safely within the centrifuge drive cup 220.

To accomplish this, the housing 1430 includes an engagement lip aroundthe opening. The spring-loading element 1410 in the housing 1430 forcesthe engagement lip 1440 against the housing mounting ring 1450. Thecentrifuge assembly of FIG. 24A shows the engagement lip on the staticseal housing 1430 contacting a disk housing mounting ring 1450,preventing disk rotation. The door of the console in this embodimentincludes a plunger 295 or similar structure, as shown in FIG. 24B, thatwill, when the door 130 is closed, engage the housing 1430; compressingthis housing against the spring-loading element 1410, and moving thehousing 1430 a fixed distance. This separates the engagement lip 1440from the mounting ring 1450; permitting rotation of the elementsmounted, directly or indirectly, on the housing mounting ring 1450. Inpractice, it may be preferable to include additional elements to improveperformance of the device. For example, with reference to FIG. 22, guide1505 may be mounted on the rotating disk cap 1500, to maintain therotating and stationary face seals 1480, 1490 in alignment, as thespring-loading element 1410 is compressed against the housing. The guide1505 may also act as a shield to prevent spattering of liquid in theevent the seal is compromised.

The CFC disk 930 is preferably keyed in angular location to the cassette490 when the centrifuge is not mounted in the console. This may beaccomplished using a tongue-in-groove that is disengaged when the rotoris pushed toward the front panel 120 by the door, or alternatively, asshown in FIG. 22, using pins 1506 on the housing mounting ring 1450, andholes 1507 in the lip 1440 of the housing 1430. This alignment of theCFC disk 930 allows appropriate positioning of the CFC disk 930 relativeto the console, and permits precise control of disk location duringpriming and other elements of the processes performed by the system asfurther described below.

Other variations are possible. For example, a stationary sleeve could beattached to a flexing annular part that attaches to the stationary faceseal or the distributor 1530. The stationary sleeve could have anannular lip extending radially inward that engages an annular lip on asleeve that rotates with and is attached to the rotor. The flexingannular part provides sufficient elastic force to make the gap zerobetween these engaged lips and provides a force that keeps the sealfaces firmly pressed together. A projection on the sleeve engages a slotor hole on the stationary sleeve to maintain angular orientation betweenthe rotor, stationary seal and the cassette. The stationary seal and itsdistributor are attached to the cassette by a cassette structure thatprovides angular alignment of the stationary seal.

With reference to FIG. 25, the face seal structure will be described inmore detail. The face seal is used for the sealing of fluid paths orducts that act as the means for transporting fluids from the cassette490 into the rotating CFC disk 930, and transporting other fluids fromthe rotating disk 930 to the stationary cassette 490.

The face seal assembly comprises a rotating ceramic (e.g., aluminumoxide) face seal and a stationary face seal 1490. The stationary faceseal 1490 may be made of carbon (e.g., carbon-graphite) or of ceramic.Although carbon has better lubricating capacities and is preferred forthat reason, the use of this material may produce an unacceptable amountof particulates. Further, ceramic wears better and may more easily bemanufactured to the appropriate “flatness.” As noted above, thespring-loading element 1410 provides sufficient force at all times thatkeep the rotating and stationary seal faces 1480, 1490 in contact witheach other. The face seal components each have a central hole 1610 andtwo or three annular channels 1445 with access holes 1620, 1621 toprovide three or four fluid paths. The rotating face seal 1480 isadhesive-bonded 1481 to the molded plastic centrifuge disk cap 1500. Thedisk cap 1500 provides fluid channel access to the ceramic fluid pathholes. The annular channels 1445 in the rotating face seal 1480 collectflow from localized holes 1620 in the stationary face seal 1490. Themating surfaces of the face seals are made extremely flat, to less thanthree helium wavelengths. This ensures sealing of all of the flat landsbetween the grooves. The outer face seal land 1550 is the only seal tothe outside or to ambient air and is the only face seal that could allowbacterial contamination of the fluids in the system from ambient air.Therefore, this outer face seal must not leak. However, the internalface seals can leak slightly without compromising blood componentquality or sterility.

A plastic molded distributor 1530 is adhesive-bonded 1491 to thestationary face seal part 1490. Flexible tubes 550 attach to the fluidducts of this distributor 1530 and connect to the manifold 510 thusconnecting stationary face seal 1490 and its fluid pathways 750 to thestationary disposable components 570 that are part of the disposablecassette 490.

This face seal assembly is made from materials used in similar bloodapplications and with similar dimensions and compressive forces. This isdone to ensure proper function and also to more easily obtain FDAapprovals, but other designs and modifications may be possible.

An alternative face seal design is shown in FIG. 26. This is very muchlike the design in the embodiment of FIG. 25, except that it has fourfluid pathways rather than three. The additional outer annular channel1580 provides a fluid path for an additional fluid 1032. This fluid maybe pumped into the CFC disk 930 through the face seal. The fluid 1032flow in its annular channel within the seal may also cool seal surfacesand provide some lubrication to the sealing faces or lands. The fluid1032 pressure may be maintained near ambient to prevent air leaks intothe storage solution from the non-sterile ambient air (if the fluid 1032pressure were very negative); and to prevent leaks out into the ambientenvironment (if the fluid 1032 pressure were very positive). Such leaksout of the seal (if only of particular fluids, such as storage solution)would not be a biohazard, or any hazard, to the user.

The skiprope, also known as the umbilical, jump-rope or seal-less,approach, is the alternative to the face seal. Various apheresis systemscurrently use the skip-rope approach. This approach is shownconceptually in FIG. 27. The CFC disk 930, with separation channel 990,and cassette 490 are shown. The CFC disk 930 may be identical to thatused in the face seal embodiment. However, in this embodiment, the meansfor transporting the fluid flows to and from the separation channel 990are not ducts, as in the previous embodiment, but a flexible plastic orelastomeric umbilical 1670 connected from the rotating CFC disk 930 tothe stationary cassette 490. This umbilical consists of a number ofsmall tubes 1690, usually three to five, depending on the function to beperformed, bonded or twisted together, or an extended multi-lumen tube.These tubes or lumens 1690 carry blood and fluids between the input andoutput ports 1692 on the disk and the cassette 490. This umbilical orskip rope 1670 is rotated about the axis or rotation 1680 of the disk atone-half the speed (RPM) of the disk itself. This keeps the umbilicalfrom twisting or winding up. The skip-rope umbilical 1670 should be asshort as possible with an outermost radius of motion around thecentrifuge disk 930 of about 3 inches or as small a radius as possible.Additionally, the length of the umbilical in the direction along theaxis 1680 of the centrifuge disk should be as short as possible.

As with the face seal embodiment, there is an inlet for (1) glycerolizedRBCs, (2) buffy coat (with PAS), or (3) unwashed RBCs (depending on theparticular embodiment of the present invention) into the CFC disk 930,and outlets for (1) deglycerolized RBCs and waste, (2) white cellproduct and platelet product, or (3) washed RBCs and waste,respectively, out of the CFC disk 930, along with inlet to provide otherinputs, as needed (i.e., additional fluid 1032). The umbilical 1670 mayuse low-cost extruded PVC tubing, the diameter of which may be selectedappropriately for the particular fluid that will travel therethrough.Thin walls of 0.015 to 0.03 inch may be used depending on themanufacturer and materials. The tubes are twisted together and may beadhesive or solvent bonded together.

A mechanism is necessary to provide the speed control, speed ratio, andthe mechanical support for the umbilical 1670 and CFC disk 930. A majoradvantage of this approach is that there is no sealing interface with apotential to leak. The umbilical provides a completely closed and, oncesterilized, sterile disposable set. This eliminates the possible risksof face seal leakage, particulates entering the blood from the seal,shear at the seal face, elevating face seal temperatures, and possibleblood damage. The umbilical, because of its bending, twisting, anduntwisting during use, possibly can heat up with time and result inblood damage. However, the short expected operating time with a maximumof 5000 RPM and good design are expected to avoid excessive heating. Itwill be readily recognized by one of skill in the art that the use ofdifferent materials may allow for longer operating time or fasteroperation without affecting the basic concepts of the invention.

The centrifuge drive mechanism, shown in FIGS. 28–31, is mounted on thefront panel 120 of the console. This entire mechanism is not much largerthan the centrifuge drive for a face-seal disk. The overall centrifugemechanism ideally should be within a cylinder of less than 7 inchesdiameter by less than 9 inches long. The centrifuge disk 930 fits, andis locked into the drive cup 220 on the console 100, which drive cup 220drives the centrifuge disk 930 at its required speed.

The disk 930 is supported on the 1-omega apparatus by a bearing assembly1720 that is part of the disposable disk 930. The disk 930 is mounted orcoupled to the cassette 490 in its sterile package before installationof the cassette 490 in the console 100. This simplifies cassette anddisk mounting by making these two parts a single assembly mounted in onesimple operation. When the cassette 490 is placed on the console frontpanel 120 and the door is closed, roller actuators 1731 in the doorengages levers or locks 1730, biased by elastomeric element 1732, thatde-mount the CFC disk 930 and allow it to rotate freely. When the dooris opened, the coupling between disk and cassette 490 recurs. This makesremoval a single, simple operation by handling only the cassette 490with the disk attached to it.

Two pinion gears 1750 mounted on support bearings 1771 in the 1-omegamechanism engage an internal gear 1740 on the CFC disk 930 and drive itat 2-omega. These gears are mounted on two short shafts 1769 that aresecured at 180 degrees apart to the umbilical drive cup 1761. This cup1761 is driven at 1-omega by the internal shaft of dual concentric driveshafts 1760.

The dual concentric drive shafts 1760 have attached pulleys that arebelt driven from two pulleys 1766, 1767 mounted on an electric motorshaft. The internal shaft of the two concentric drive shafts 1760 drivesthe umbilical drive cup 1761, which couples with and drives theumbilical at 1-omega.

The external tubular concentric shaft has two pulleys mounted to it thatbelt drive 1768 the two short shafts 1769 secured to the umbilical drivecup 1761. These shafts are secured but rotate freely in bearingassemblies 1771 that are part of or attached to the umbilical drive cup.These shafts have pinion gears 1750 that engage an internal ring gear1740 that is part of the CFC disk 930. One such shaft and gear isadequate to directly drive the CFC disk 930, but two at 180 degreesapart are used for balance and safety via redundancy.

The concentric drive shafts rotate within a bearing block 1797 that ismounted to stationary hollow cylinder 1798 with one flat end. Thiscylinder 1798 is attached to the console front plate 120 and supportsthereby the entire mechanism.

As another alternative, shown conceptually in FIGS. 32 and 33, ratherthan engaging an internal gear 1740 on the CFC disk itself, the piniongears 1750 engage a similar internal gear 1741 on a disk drive cup 1762,which is mounted in the umbilical drive cup 1761. Toothless rotorsupport bearings 1752 provide additional stability and centering of thedisk drive cup 1762. The disk drive cup includes a slot 1763 to allowthe umbilical to be placed into the umbilical drive cup. The disk drivecup may then include pins 225 as described in connection with the cup220 to hold the centrifuge disk in the cup when in operation. Persons ofordinary skill in the art will appreciate that other design alternativesare possible, including an external gear on the disk drive cup (or theCFC disk) surrounded by the drive gears and/or support bearings.

To reduce noise, gears and support bearings may be plastic orelastomeric.

Operation of a Continuous Flow Centrifuge

In various embodiments of the instant invention, the CFC may be used to:(1) separate glycerolized RBCs into deglycerolized RBCs and wasteproduct (i.e., a volume of glycerolizing solution plus some plasma andred cell storage solution), (2) separate buffy coat (with PAS) intowhite cell product and platelet product, and (3) separate unwashed RBCsinto washed RBCs and waste product. The operation of the CFC issubstantially similar in each embodiment; various blood products and/orliquids are separated by weight via centrifugation. It will thus bereadily understood by those of skill in the art that the followingdescription of the operation of the CFC with respect to the separationof a glycerolized RBCs into deglycerolized RBCs and waste product issubstantially similar to the operation of the CFC with regard to theseparation of alternate blood products.

The separation of glycerolized RBCs into deglycerolized RBCs and wasteproduct in a CFC will now be described. The compact, disposable CFC disk930 is designed to provide blood product separation into variouscomponents within an annular separation channel 990 and to remove thesecomponents from the channel and disk, meeting the various requirementsfor flow rate, hematocrit, blood component damage, and the like. Aconceptual design of the CFC disk 930 is shown in FIG. 34. GlycerolizedRBCs are pumped into the CFC disk 930 via the entry duct 1000 andthrough an input port 1220 while the disk rotates around the axis 1200at sufficient speed to rapidly separate incoming glycerolized RBCs intodeglycerolized RBCs and waste product. The centrifuge disk 930 has anannular separation channel 990 near its outer periphery. GlycerolizedRBCs flow continuously into this separation channel 990, separating intocomponents as the glycerolized RBCs flow along the channel, and thecomponents are removed at various ports along the channel.Deglycerolized RBCs 1010 are separated to the outer (larger diameter)wall of the separation channel 990, and waste product 1030 separates tothe inner wall 1117 of the channel. The deglycerolized RBCs 1010 andwaste product 1030 are removed continuously through ports and ducts toproduct bags.

The separation channel 990 is shaped to improve the separation andremoval of deglycerolized RBCs 1010 and waste product 1030. The channelouter wall 1118 increases in radius (from the axis of rotation 1200) inone region to be at or near its maximum distance or radius 1170 from theaxis of rotation 1200 and thus form a collection pocket portion 1060 fordeglycerolized RBCs. The red cell pick-up port 1120 removes red cells ator near the bottom or largest radius 1170 of this pocket, at thegreatest distance from the center of rotation. This increased radiusincreases the depth of the red cell layer (the radial distance from thered cell-waste product interface 1130 to the red cell pick-up port) andprovides the maximum g-force and packing of red cells at this port. Thismaximizes the packed red cell hematocrit that can be achieved for cellsremoved through the red cell pick-up port at any given rotational speedof the disk. The deep red cell layer also minimizes the pulling of wasteproduct 1030 through this layer to the red cell pick-up port.

FIGS. 35 and 36 show designs for the packed red cell removal region. Anarrow gap 1120, of a width substantially less than the average radialwidth of the separation channel 990, and generally between 10 to 30mils, is provided over part or all of the separation channel 990, at thedeepest, that is the largest radius 1170 from the spin axis 1200, partof the channel and of the red cell collection pocket portion 1060. Thisgap 1120 is used to pull red cells from the deepest part of the pocketwhere they are most highly packed, to a high hematocrit (about 90%).This narrow gap 1120 ensures that red cells are removed from the highesthematocrit region of the concentrated red cells 1010. The gap is narrowenough to cause a slight restriction and ensure that lower-hematocritred cells or waste product 1030 from near the red cell-waste productinterface 1130 does not channel through the concentrated red cells 1010and out this removal port. The radial distance from the red cell-wasteproduct interface 1130 to the packed red cell removal port 1040 is madesufficiently great to prevent such channeling and maximize red cellhematocrit.

The length of this gap is maximized in the axial direction, that is,essentially parallel with the axis of rotation, so that the flowvelocities are low, to avoid damage to the red cells. Further, theentrance to the gap may be defined by material having a radius 1121 thatis greater than or equal to the width of the gap 1120 to prevent damageto the red cells and reduce the pressure drop.

The channel inner wall 1117 may decrease in radius 1180 from the axis ofrotation 1200 to form a waste product pocket portion 1100 where wasteproduct 1030 can flow through an output port 1090 into a substantiallyradial waste product removal duct 1070, which can include other fluidtransportation means such as a tube, that transports the waste producttoward the center of the disk 930 for removal to the cassette 490. Thedecreasing radius at an increasing cross-sectional area for wasteproduct flow results in a reduced waste product flow rate and the finalopportunity for stray cells to separate out of the plasma stream beforewaste product 1030 is removed.

Once the operation is complete, the system must be purged. There areseveral ways of performing this task. In the first method, plasma 1030is removed from the plasma removal duct 1070 during steady-statecontinuous flow operation. When the blood processing operation iscomplete, the separation channel 990 is filled with separated blood. Thered cell pump 701 continues to remove red cells from the red cellcollection pocket portion 1060 until all red cells are removed whiledisk rotation continues at a high speed. Plasma 1030 is allowed to flowback from the plasma bag and fills the separation channel 990. Theseparation channel 990 is now filled with plasma 1030. However, thereare residual red cells loosely adhering to the walls of the separationchannel 990. This prevents draining the plasma 1030 out the plasmaremoval duct 1070 while slowly rotating the disk because the residualred cells will mix with this plasma and overly contaminate it. It isalso not feasible to pump the plasma 1030 out of the concentrated redcell removal duct 1050 because this duct is filled with red cells. Anexcessive amount of plasma would be needed to clear out or purge the redcells sufficiently to avoid excessive red cell contamination of theplasma 1030. Therefore, as shown in FIGS. 38A and 39, a second plasmaremoval duct 1080 and port 1095 may be added to the disk 930specifically to remove plasma 1030 during the purge process when theseparation channel 990 is filled with plasma 1030. In the embodimentshown, the second plasma removal port is added in an “island” 1650 nearthe red blood cell “pocket” portion 1060 of the separation channel 990.The disk 930 is rotated at a moderate speed and sterile air, which wascollected in an air bag 1110 during disk priming, is used to replace theplasma 1030 in the separation chamber as plasma 1030 is removed throughthe second plasma removal port 1095. The air pressure may be greatenough to force the plasma 1030 out of the disk or a pump may be used topull the plasma out of the disk.

The separation channel design, including the location of ducts, and diskrotational speed are key to achieving the desired separationrequirements. FIGS. 37, 38, 42, 43, 44 and 45 show various alternativedesigns for the substantially circular separation channel, in that theaxis of rotation 1200 is the center of a circle approximately defined bythose portions of the separation channel that are not in the pocketportions 1060, 1100. It is not necessary, however, that the separationchannel extend for a full 360 degrees, or that the channel be unbroken,although as noted below, such a design may have certain advantages.

In all the designs, the glycerolized RBCs enter the separation channelat a port 1220, concentrated (deglycerolized) red cells 1010 are pickedup in port 1040 from a pocket portion 1060 positioned at the largestradius 1170 or point furthest from the axis of rotation 1200, and wasteproduct removed at the port 1090 at the other end of the separationchannel 990.

In all of the designs a variety of radial fluid conduits 1001 may beused. For example the ducts 1070, 1050, 1251 and 1000 may be machined inthe disk body 1150 substantially extending toward the center of the disk930. The ducts are sealed at 1151 by the disk cap 1500. These fluidducts carry glycerolized RBCs to the separation channel 990 from thecentral face seal. Waste product and concentrated (deglycerolized) redcells are carried by these ducts from the separation channel 990 to theface seal. Alternatively, tubing is used in the skip rope CFC design,but tubing may also be used as a radial fluid conduit in the face sealdesign.

FIGS. 38A, 38B and 39 illustrate a CFC disk 930 specifically designedfor umbilical tubing 1210 attachments. Glycerolized RBCs enter at theentry port 1220 through a tube 1260 which is connected to the separationchannel 990 and which is 180° away from the component removal region1270. Glycerolized RBCs are divided into two paths that are on eitherside of the tube 1260. This reduces (by half) the flow rate in each 180°channel segment and may improve red cell-waste product separation.Concentrated red blood cells 1033 are channeled through a pocket formedby an island 1650 in the separation channel 990 and through narrow gap1120 into a slot 1230 formed in the island 1650 with an opening towardthe outer wall 1118 of the separation channel 990. The slot entrancedoes not extend the entire axial length of the separation channel, thatis, in the direction parallel to the axis of rotation. Generally, theslot represents 50% to 90% of the length. Alternatively, holes can beplaced at the entrance rather than a slot. Waste product is removedthrough a removal port 1090 during steady-flow, which may be positionedon the inner wall 1117 of the separation channel 990 as shown, oralternatively (not shown) on that portion of the island 1650 closest tothe inner wall. Umbilical tubing 1210 attaches to the ports at or nearthe entry port 1220 and the component removal region 1270. However,ducts to a face seal as described above can also be used instead of anumbilical, with the same separation channel and component removal designfeatures.

FIGS. 42, 43 and 44 show alternative designs for a circular separationchannel 990. Each of these embodiments has radial inlet and outletducts. FIG. 42 shows a CFC disk 930 with features such as a collectionpocket portions 1060 and narrow gaps 1120. The system can be designedsuch that glycerolized RBCs enter at a port at point 2210, 180° from theremoval port 1040 and waste product is removed at a port at point 2220at an angle less than 90° from the glycerolized RBC removal port 1040,or alternatively, glycerolized RBCs can enter at point 2220 and wasteproduct can be removed at point 2210.

The embodiment of FIG. 43 also includes two ports that may alternativelybe used for waste product removal or glycerolized RBC introductiondepending upon the connections made to the manifold. One port ispositioned at point 2230 adjacent and parallel to a red blood cellremoval port 1040, while the other port at point 2240 is positioned atan angle of from 90 to 270 degrees relative to the red blood cellremoval port 1040. An internal barrier wall 2251 is positioned adjacentand parallel to the red blood cell removal port 1040, but on theopposite side of the red blood cell removal port 1040 from point 2230.The embodiment may also include a red blood cell collection pocket 1060and gap 1120, and may also include a knife edge diverter 1320 which isfurther described below.

In FIG. 44, a glycerolized RBC entry port 1220 is positioned 180 degreesfrom the red blood cell removal port 1040. A waste product removal port1090 is positioned adjacent and parallel to the red blood cell removalport 1040. The two ports are separated by an internal barrier wall 2251.As with the embodiment shown in FIG. 43, a narrow gap 1120 and pocketportion 1060 may be included to assist in the separation of theconcentrated red blood cells 1033.

Finally, in FIGS. 45A and 45B, a circular separation channel 990 withouta barrier is used. The red blood cell removal port 1040, in a pocketportion 1060 formed in the outer wall 1118 is positioned 180 degreesfrom the glycerolized RBC entry port 1220. Also at 180 degrees from theglycerolized RBC entry port 1220, but positioned in a pocket portion1100 in the inner wall 1117, is the waste product removal port 1090.This design has similar advantages to the design shown in FIG. 38; forexample, glycerolized RBCs are divided into two paths at theglycerolized RBC entry port 1220 reducing by half the flow rate in each180° channel segment and potentially improving red cell-waste productseparation. Optionally, as shown in FIG. 45B, an island structure 2250may be used. The island structure 2250 allows the formation of narrowgaps 1120 near the entrance to the red blood cell removal port 1040.

In all designs in which an island structure 2250 or an extension fromthe inner wall 1117 is practical, a knife edge diverter 1320 may be usedto separate waste product from the concentrated red cells 1010. Thepoint 2271 of the knife edge diverter 1320 may be at a slightly smallerradius from the center of rotation 1200 than the radius of the redcell-waste product interface 1130, as shown in FIG. 37. The wasteproduct in the channel from this diverter 1320 to the waste productpick-up 1090 spirals or steps inward to ensure only waste product is inthis channel; red cells will separate out from waste product in thischannel segment and move upstream under centrifugal forces to return tothe channel segment containing red cells.

With reference to FIGS. 38B and 47B, current standard designs forseparation channels usually have inner and outer walls 1118 that aresubstantially parallel with each other as shown in 38B, or slightlytapered, as shown in FIG. 47B. However, control can be improved; forexample in the purging process, by utilizing a cross-sectional shapesimilar to that shown in FIG. 46. The walls of the separation channelare generally tapered, and the channel 990 becomes substantially“shallower” at the inner wall 1117, as the inner wall 1117 forms arounded edge 1119. By placing the waste product removal port 1090 withinthe shallower section of the inner wall 1117, and the red blood cellremoval port at the “deeper” section of the channel 990 and at the outerwall 1118, mixing or contamination of waste product 1030 and red bloodcells 1010 is less likely, given the position of the waste product-redblood cell interface 1130 relative to the channel and the ports.

An alternative design for the removal of waste product in the separationchannel 990, one during steady flow and one during the purge, is shownin FIGS. 40 and 41. A spring-loaded 1290 ball shuttle valve 1280 is usedto control which port 1090, 1095 removes waste product. The ball shuttlevalve 1280 includes a ball 1281 attached to a spring in a housing 1282with three openings. One opening is attached to the waste productremoval port 1090 for continuous flow, while another is connected to thewaste product removal port 1095 for purging. The third opening isconnected to a waste product removal duct 1070 or similar structure.During steady state continuous flow operation shown in FIG. 28, the CFCdisk RPM is high (perhaps 4000 to 5000 RPM) and the g-forces on the ball1281 compress the spring and close the purge port, with the steady flowport open to remove waste product 1030.

During the purge shown in FIGS. 41A and 41B, the RPM is droppedsubstantially (to perhaps 1000 RPM). This permits the spring force toovercome the g-force. The ball shuttle valve 1280 thus closes the steadyflow port 1090 and opens the waste product purge port 1095. The wasteproduct 1030 is either pumped out during the purge, or the pressure ofair (entering the separation channel and displacing waste product) isused to force the waste product out as was described above in otherembodiments.

It is not necessary that the separation channel be centered on the axisof rotation of the disk or be circular. FIGS. 47A and 47B show aseparation channel 990 that extends about 420 degrees. This channel 990may, as shown, have an outer wall 1118 spiral of increasing radius fromthe glycerolized RBC entry port 1220 to concentrated red cell pick-up atport 1040, and the channel may be of decreased radius from theglycerolized RBC entry port 1220 to collect waste product at port 1090.The design may optionally include other features discussed above, suchas a knife edge diverter 1320.

FIG. 48 shows a CFC disk 930 with a slightly spiral separation channel990 that extends approximately 360° around the CFC disk 930 periphery.The design is substantially circular in that is it is based on a circle1190, but unlike the circular embodiments described above, thecenterpoint of the circle 1201 that is defined by the separation channel990 is offset from the axis of rotation 1200, and the channel 990 mayspiral inward slightly at the waste product port 1090. In some cases,the inward spiral may be continued past 3600 to form two concentricseparation channels for a portion of the disk.

FIG. 49 shows a CFC disk 930 with another separation channel designwhere the separation channel 990 extends beyond 360° to 420°. Thereasons for extending the channel are to provide greater separation pathlength for red cell packing or concentration, achieving a higherhematocrit packed red cell product 1010, or a greater separation pathlength for waste product 1030 (and a smaller radius) to obtain betterwaste product removal with cellular contamination.

Optical Sensor Control of the Red Cell-Plasma Interface

FIG. 50 shows the design concept used to detect and measure the locationof the waste product-red cell interface within the separation channel ofa rotating centrifuge disk 930 using a sensor 2170 incorporating anoptical detector 2171. A light source 2120 is turned on for a very shorttime (an arc of about one degree) each rotation of the CFC disk 930 toilluminate a short angular segment or region of the separation channel990 across all or part of the radial width of this channel. FIG. 50shows a location of this optical sensing region. The red cell layer 1033blocks the passage of light but the waste product layer 2160 transmitsthis light to an optical detector 2171. The optical detector 2171receives an amount of light proportional to the radial width of thewaste product 2160 in the separation channel 990 determined by thelocation of the red cell-waste product interface 1130. The analogdetector output increases when this interface moves radially outward anddecreases when it moves radially inward. This detection of the interfacelocation is used during continuous-flow operation in a feedback loop tocontrol the pump flow rates in the system. In operation a desiredreference interface location is established for a particular process(for example, maintaining the interface at a particular positionrelative to the point of a knife edge diverter) and the actual locationof the interface 1130 is measured by the described optical means. Theerror signal of actual minus reference location (which are the opticalanalog values) is used to change flow rate ratios in proportion to theerror signal with appropriate time constants or averaging. This systemand method can thus maintain the red cell-waste product interface 1130in its desired location. Another optical detector 2171 can be placed toprovide information about the conditions just outside the waste productremoval port 1090.

As noted above, the CFC and cassette components may be made of clearplastic to allow for the use of optical detectors. To preventscattering, it may be advantageous to place an opaque barrier on thedisk and/or cap in the region of interest. The opaque barrier includes ahole so as to more precisely direct the light beam from the light source2120.

An optical detector 2171 may also look at one or more additional regionsin the separation channel 990. One additional region may be identical tothe first measurement region but is modified to provide an accurateradial distance calibration. An additional opaque barrier may be addedover the red cell portion of the separation channel in this region. Thisbarrier extends into the waste product portion of the channel to provideonly a waste product radial distance seen by the optical sensor. Thisfixed distance and the optical output represent a fixed hematocrit. Thiscan be used to calibrate the optical sensor output in the measurementregion. Such a calibration will compensate for changes in waste producttransmissibility, light source intensity, light scattering, and lightabsorption through CFC disk surfaces.

EXAMPLES

The current invention is able to use one console or electromechanicalinstrument to perform multiple blood treatment processes. Each processrequires a different disposable set or product specifically designed toimplement that process in combination with specific software for eachprocesses.

For all processes shown schematically in FIGS. 51–60 the disposable setdescribed above is removed from a sterile package and hung on the pinsof the console. Solution bags or bottles are either attached by theoperator using the Luer-lock, spike or other attachments means. The bagsor bottles could also be pre-attached. Bacterial filters (e.g., 0.2micron) may be placed in the flow paths from these bags to ensure themaintenance of sterility. The bags are hung in designated locations onthe console.

The console “calibration” button is depressed and calibrations andsystem software status are checked. Data collection may be performedmanually by the operator using a bar code wand reader (not shown) andautomatically via the bar code reader console.

Various ways of implementing the processes contemplated by the instantinvention are illustratively depicted in the schematic diagrams of FIGS.51–60. It will be understood that these Figures are intended asnon-limiting examples of processes and that a feature of the inventionis that other processes can be performed by selecting and implementing adifferent series of operations and states.

Example 1 Automatic Glycerolization of Standard Unit of Packed RBCs inStorage Solution

Red cells are collected from a donor in a standard bag with a standardanticoagulant. They are concentrated by standard methods to a hematocritof about 90% and storage solution is added. This bag of a standardpacked RBC blood component is then attached with a sterile dockingdevice to the sterile disposable set, using a cassette configured for aglycerolization process that interacts with the control module. Glycerolsolution is in a bottle attached to the disposable set using a standardspike; although it will be readily apparent to one of skill in the artthat solutions other than glycerol may be used in accordance with thisembodiment of the present invention. Sterility is achieved by using abacterial filter for glycerol added to the RBCs. Glycerol solution isslowly added based on RBC volume. Then, the RBCs are concentrated, byremoving fluid, to a hematocrit of about 75% to 80%. Glycerolized RBCsare stored in the glycerolized RBC freezing bag. They can now be frozenand stored in a −80° C. freezer.

More specifically, as illustratively depicted in FIGS. 51 and 52, thepresent invention may be configured as a system 5100 to implement aglycerolization process. With reference to FIG. 51, such a system 5100may include a recirculation bag 5125 connected to a bag of packed RBCsin storage solution 5122 and a glycerol (e.g., 57% glycerol) bottle5121. The bag of packed RBCs 5122 is connected to the system 5100 via asterile dock 5171, and the glycerol bottle 5121 is connected by astandard spike 5161. A bacterial filter 5151 is additionally included tomaintain sterility of the system 5100. The recirculation bag 5125further includes a spray nozzle 5195 that provides a conical spray ofglycerol solution into the contents of the recirculation bag 5125. Amixer or shaker apparatus 5193 is also included, to continually mix thecontents of the recirculation bag 5125. A satellite bag 5123 and frozenred cell product bag 5124 are additionally included in the system 5100.Fluid communication between the satellite bag 5123 and frozen red cellproduct bag 5124 and the remainder of the glycerolization system 5100 iscontrolled by manual clamps 5162, 5163.

A glycerol pump 5101 and blood pump 5102 are included to pump thevarious fluids through the system 5100. Pressure measurement devices5111, 5112 are included to monitor the flow of the various fluidsthrough the tubing, and ultrasonic air sensors 5131, 5132 are furtherincluded to monitor the flow of air through the tubing (e.g., todetermine when the fluid contents of a particular bag have beenevacuated). A microprocessor or other, similar electronic device (notshown) collects the information from the pressure measurement devices5111, 5112 and ultrasonic air sensors 5131, 5132 and controls the valves5141, 5142 and pumps 5101, 5102 accordingly, to implement theglycerolization process of this embodiment of the present invention.Additionally, the bags and various other components of the system areconnected to one another by tubing in communication with a cassette (notshown) designed specifically for the operation of this embodiment of thepresent invention, as discussed in greater detail above.

To implement the process of this embodiment of the present invention, aglycerolization solution may be added to RBCs by controlling the flowrate, dispersion and mixing of glycerolizing solution into the RBCvolume. An RBC bag 5122 is sterilely docked to the disposable set. TheRBCs are transferred (pumped) from their product bag 5122 to arecirculation bag 5125 that is part of the set. The RBCs are pumped at aconstant flow rate until the product bag 5122 is empty. Then, the timeand volume of RBCs transferred are known. The total volume ofglycerolizing solution is a fixed ratio to this transferred red cellvolume. The pump 5101 that pumps the glycerolizing solution iscontrolled to achieve this volume. The pump flow rates and times and thestep by step sequence of operations are controlled by the microprocessorand software specific to this process.

Dispersion of glycerolizing solution into the RBC volume in therecirculation bag 5125 is achieved by a conical spray of solutionproduced within this RBC volume. This spray distributes droplets ofsolution into the red cell volume, achieving dispersion and some mixingand reducing localized high concentrations of glycerolizing solution inthis RBC volume. High concentrations and poor mixing may result in RBCdamage. A spray nozzle 5195 at the end of a tube inside therecirculation bag 5125 achieves this conical spray. The bag 5125contents are also continuously mixed using a bag shaker 5193.

The glycerolized RBCs are then transferred to another bag 5124 that issuitable for placement in a standard blood bank centrifuge bucket. TheRBCs and glycerolizing solution are separated and a percentage ofglycerolizing solution is removed. This is performed to achieve about60% to about 80% hematocrit red cells, to reduce the total volume ofglycerol and RBC bag volume, and aid in the removal of glycerol in asubsequent deglycerolization (wash) procedure after the frozen RBCs havebeen thawed. A large volume of glycerol is needed in the glycerolizationprocess because of dilution by the plasma and storage solution mixedwith the RBCs.

As illustratively depicted in FIG. 52, the system 5200 of the presentinvention may be configured for a concentration operation to concentrateRBCs for freezing (e.g., as part of a glycerolization process). Thisconfiguration of the system 5200 includes a recirculation bag 5221connected to a bag of packed RBCs in storage solution 5226 and aglycerol bottle 5225. The bag of packed RBCs 5226 and glycerol bottle5225 are connected to the system 5200 with standard spikes 5261, 5262. Abacterial filter 5251 is also included to maintain sterility of thesystem 5200. The recirculation bag 5221 further includes a spray nozzle5295 that provides a conical spray of glycerol solution into thecontents of the recirculation bag 5221. A mixer or shaker apparatus 5293may also be included, to continually mix the contents of therecirculation bag 5221. A glycerolized RBC bag 5222 and waste productbag 5223 are additionally included in the system 5200. A free plasmahemoglobin sensor 5281 is included, as well.

A CFC 5291 is included, as described in greater detail above. In thisconcentration embodiment of the present invention, the CFC 5291separates glycerolized RBCs from a waste product (e.g., glycerolizingsolution, some plasma and RBC storage solution); thereby concentratingthe RBCs. An optical detector 5292 is included with the CFC 5291 tomonitor the operation of the CFC 5291, as described above.

A glycerol pump 5202, recirculation pump 5201 and RBC pump 5203 areincluded to pump the various fluids through the system 5200. Pressuremeasurement devices 5211, 5212, 5213 are included to monitor the flow ofthe various fluids through the tubing, and ultrasonic air sensors 5231,5232 are further included to monitor the flow of air through the tubing(e.g., to determine when the fluid contents of a particular bag havebeen evacuated). A microprocessor or other, similar electronic device(not shown) collects the information from the pressure measurementdevices 5211, 5212, 5213, ultrasonic air sensors 5231, 5232, free plasmahemoglobin sensor 5281 and optical detector 5292, and controls thevalves 5241–5247, pumps 5201, 5202, 5203 and CFC 5291, accordingly, toimplement the concentration process. Additionally, the bags and variousother components of the system are connected to one another by tubing incommunication with a cassette (not shown) designed specifically for theoperation of this embodiment of the present invention, as discussed ingreater detail above.

The glycerolized RBCs are concentrated (a volume of glycerolizingsolution plus some plasma and RBC storage solution are removed) usingthe CFC disk 5291. This is a recirculation process in which RBCs areremoved from the recirculation bag 5221, fluid is separated anddiscarded, and the RBCs (at a higher hematocrit) are returned to therecirculation bag 5221 (while the bag 5221 is being shaken and itscontents mixed). This occurs until a specific hematocrit is achieved inthe recirculation bag 5221. The hematocrit is known by the ratio ofoutlet RBC pump flow rate and inlet blood flow rate. An optical detector5292 is used to maintain a fixed location in the CFC separation channelby varying the RBC pump flow rate in a feedback loop with the opticaldetector 5292 providing a signal proportional to the red cell-plasma(i.e., waste product) interface location.

The glycerolized RBCs are then pumped out of the recirculation bag 5221and into a bag suitable for freezing 5222.

Example 2 Automatic Deglycerolization of RBCs

The system of the present invention may be used to automaticallydeglycerolize (i.e., RBC washing and removal of glycerol and free plasmahemoglobin) a unit of glycerolized, frozen and then thawed RBCs;although it will be readily apparent to one of skill in the art thatsolutions other than glycerol may be removed in accordance with thisembodiment of the present invention. The overall approach fordeglycerolization is to mix the glycerolized RBCs first with ahypertonic solution that shrinks the RBCs and expels some of theglycerol from the RBCs. Then, the RBCs are washed in an isotonicsolution to remove glycerol and free plasma hemoglobin from the fluidsurrounding the RBCs. During this wash process, glycerol diffuses out ofthe cells and the RBCs return to normal volume.

As illustratively depicted in FIG. 53, the present invention may beconfigured as a system 5300 to perform an automatic deglycerolizationprocess. In this configuration, the system 5300 includes a recirculationbag 5321 with a blood filter 5355, connected to a set of three solutionbags 5324, 5325, 5326 (e.g., for containing (1) a hypertonic solution,(2) an isotonic wash solution and (3) a red cell additive or storagesolution, respectively) and a bag of thawed, glycerolized RBCs 5323. Thebag of thawed RBCs 5323 is connected to the system 5300 via a steriledock 5371, and the three solution bags 5324, 5325, 5326 are connectedwith standard spikes 5364, 5365, 5366, respectively. Bacterial filters5351, 5352 are additionally included to maintain sterility of the system5300, and a static mixer 5394 is included to assist in mixing the RBCswith the various solutions contained in the solution bags 5324, 5325,5326. A mixer or shaker apparatus 5393 may also be included, tocontinually mix the contents of the recirculation bag 5321. Adeglycerolized RBC bag 5322 and waste product bag 5327 are additionallyincluded in the system. A free plasma hemoglobin sensor 5381 isincluded, as well.

A CFC 5391 is included, as described in greater detail above. In thisconcentration embodiment of the present invention, the CFC 5391separates RBCs from a waste product (e.g., glycerolizing solution, someplasma, RBC storage solution and solutions from solution bags). Anoptical detector 5392 is included with the CFC 5391 to monitor theoperation of the CFC 5391, as described above.

A thawed RBC pump 5301, solution pump 5302, blood pump 5303 and RBC pump5304 are included to pump the various fluids through the system 5300.Pressure measurement devices 5311, 5312, 5313, 5314 are included tomonitor the flow of the various fluids through the tubing, andultrasonic air sensors 5331, 5332, 5333, 5334 are further included tomonitor the flow of air through the tubing (e.g., to determine when thefluid contents of a particular bag have been evacuated). Amicroprocessor or other, similar electronic device (not shown) collectsthe information from the pressure measurement devices 5311, 5312, 5313,5314, ultrasonic air sensors 5331, 5332, 5333, 5334, free plasmahemoglobin sensor 5381 and optical detector 5392, and controls thevalves 5341–5348, pumps 5301, 5302, 5303, 5304 and CFC 5391,accordingly, to implement the deglycerolization process. Additionally,the bags and various other components of the system are connected to oneanother by tubing in communication with a cassette (not shown) designedspecifically for the operation of this embodiment of the presentinvention, as discussed in greater detail above.

In operation, a frozen glycerolized RBC bag 5323 is thawed in a standardfashion. A deglycerolization cassette (not shown) is inserted into thecontrol module. The disposable set bags are hung. The solutions are hungand spiked. The thawed glycerolized RBC bag 5323 is hung and attachedwith a sterile docking device 5371 to a disposable set. Therecirculation bag 5321 is mounted on the bag shaker 5393. The STARTbutton is depressed and the display indicates “Prime System,” and theprocess timer in the display indicates time from start.

The solution pump 5302 is used to add the solutions at the required flowrates and with the required equilibration times to the recirculation bag5321. Solenoid operated finger-type pinch valves 5341–5348 are used topinch closed or open the tubing selectively to turn fluid flows on oroff. These pinch valves 5341–5348 are computer-controlled, and aregenerally of the type that have been used successfully and reliably onconventional autotransfusion, apheresis and hemodialysis systems. Halleffect sensors (not shown) independently confirm the proper opening andclosing of these valves 5341–5348. Pinch valves 5341–5348 are opened orclosed to select the appropriate solution for the initial dilutions, andthe solution pump 5302 adds these solutions to the recirculation bag5321 after the RBCs have been pumped into this bag 5321 from theglycerolized RBC bag 5323. All saline and storage solutions pass througha bacterial filter 5351, 5352 to ensure sterility.

In the subsequent deglycerolization process, the solution pump 5302 addssaline to blood as it exits the CFC 5391 using the RBC pump 5304 duringblood recirculation. The solution pump 5302 also is used to prime thesystem 5300 with saline (i.e., fill all blood lines with saline andeliminate air) during a pre-dilution stabilization period. The solutionpump 5302 is used to add storage solution at the end ofdeglycerolization and to purge blood out of the CFC 5391 and lines bypumping solution through these devices and pushing blood ahead of thesolution into the deglycerolized RBC bag 5322.

The blood pump 5303 is used to pump blood out of the recirculation bag5321 and into either the recirculation bag 5321 or the deglycerolizedRBC bag 5322. Blood pump timing and flow rates are computer-controlled.A blood particulate filter sac 5355 in the recirculation bag 5321 isused to eliminate particulates, clots and white cell agglomerates thatform during the deglycerolization process. The blood pump 5303, solutionpump 5302, RBC pump 5304 and thawed RBC pump 5301 flow rates arecontrolled to achieve rapid, optimal deglycerolization by recirculationof blood through the CFC 5391 with waste removal, followed by washsolution (e.g., 0.9% saline, 0.2% glucose) addition.

Pressure measurements are made by pressure transducers 5311, 5312, 5313,5314 in the control module. Diaphragm pressure isolators are used toobtain an impervious barrier and ensure sterility. The pressuremeasurements are made for the following reasons: to control the limitsof CFC 5391 operation (e.g., measuring inlet pressure); to ensureproper, safe system operation within acceptable pressure ranges; and toinform the user when bags are full or empty (i.e., by pressure increasesor decreases). Ultrasonic sensors 5331, 5332, 5333, 5334 are used todetect air; indicating when bags are empty and to determine andterminate pump flow when the glycerolized RBC bag 5323, solution bags5324, 5325, 5326 or recirculation bag 5321 are empty.

The pressure measurements, the mode selection (i.e., glycerolization ordeglycerolization) by the user, and the control logic for that modeprovide inputs to the computer (i.e., microprocessor) controller. Theoutputs controlled by the computer include the timing (i.e., on/off) andspeeds (i.e., fluid flow rates) of the pumps 5301, 5302, 5303, 5304 andthe timing (i.e., on/off) of the tubing pinch valves 5341–5348.

More specifically, as illustratively depicted in FIG. 53, adeglycerolization process may be performed with the system 5300 of thepresent invention with three solutions: a hypertonic solution in a firstsolution bag 5324 (e.g., 12% NaCl); an isotonic wash solution in asecond solution bag 5325 (e.g., 0.9% NaCl, 0.2% glucose); and a red celladditive or storage solution in a third solution bag 5326 (e.g., AS3NUTRICEL® Additive Solution; available from Gambro BCT, Inc., Lakewood,Colo.). An objective of this process and system is steriledeglycerolization and long-term refrigerated storage (e.g., at least twoweeks) of the deglycerolized red cell product. The storage solution isselected to achieve this two-week (or longer) refrigerated storage afterdeglycerolization.

The hypertonic solution is pumped by the solution pumps 5302 and thethawed glycerolized RBCs are simultaneously pumped by the thawed RBCpump 5301 through a static mixer 5394 and into a recirculation bag 5321,which is shaken to achieve good mixing. The flow rate ratio of thesolution to the RBCs is fixed at an optimal value for minimal hemolysis.This process step ends when the thawed deglycerolized RBC bag 5323 isempty and all RBCs are in the recirculation bag 5321. Ultrasonic airdetector 5332 detects when the thawed deglycerolized RBC bag 5323 isempty. Thus, the volume of hypertonic solution is dependent upon thevolume of thawed RBCs and is maintained at a ratio that minimizeshemolysis and maximizes RBC recovery.

An equilibration interval of about 2 to 5 minutes then occurs in whichthe recirculation bag 5321 is shaken and its contents mixed. The RBCsbegin to shrink in this process step, expelling glycerol. Shrinking theRBCs to a near optimal size, at a near optimal rate may minimizehemolysis. The RBC size may reduced sufficiently in this process step,so that, in subsequent steps (e.g., the isotonic saline wash) the RBCsdo not rupture, causing excessive hemolysis occurs.

The next process step is to introduce additional hypertonic solutionfrom solution bag 5324 at a rate and a volume that is optimal forminimal hemolysis. Since the total volume of thawed RBCs is known fromthe flow rate and duration of pumping with the thawed RBC pump 5301 intothe recirculation bag 5321, the desired fixed volume ratio of hypertonicsolution to RBCs can be calculated and the solution pump 5302 controlledto achieve this volume. This hypertonic solution volume is added whilethe bag shaker 5393 is shaking and mixing the recirculation bag 5321contents.

The next process step is to pump blood from the recirculation bag 5321(using the blood pump 5303) into the CFC 5391, and pump cells out of theCFC 5391 (using the RBC pump 5304) back to the recirculation bag 5321.Waste fluid is expelled from the CFC 5391 to the waste bag 5327.Isotonic solution (i.e., wash solution) is pumped by the solution pump5302 out of the isotonic solution bag 5325 into the RBC flow streamafter the RBC pump 5304. The blood pump flow rate is more or less fixedat an optimum of about 200 to 300 mL/min. The RBC pump 5304 iscontrolled by the optical detector 5392 to maintain a fixed redcell-plasma interface location within the CFC 5391 disk separationchannel. The ratio of RBC pump flow to blood pump flow is proportionalto entering blood flow hematocrit and to CFC 5391 disk rotational speed.The latter is kept constant. The hematocrit in the recirculation bag5321 is kept constant by changing the flow rate of isotonic solutioninto the RBC stream, using the hematocrit value calculated from blood5303 and RBC pump 5304 flow rates in this feedback control loop. Anothermethod of hematocrit control may also be used: two pressure sensors ateither end of a laminar flow element (shown, e.g., in FIG. 59 aselements 5911, 5912 and 5997) may be used along with a temperaturesensor (not shown) in the blood line entering the CFC 5391 disk tomeasure blood pressure drop, which correlates directly with viscosityand hematocrit.

The recirculation process removes fluid (i.e., waste product) from theblood and replaces it with isotonic solution in a continuousconcentration and dilution process. The optimal hematocrit values for arapid, efficient wash are about 45% entering the CFC 5391 disk to about65% leaving the disk. This wash process step time is about 15 minutes,with 1750 to 2000 mL of isotonic solution consumed. A short wash andoverall process time may be desirable to maximize the number of units offrozen RBCs that can be washed per hour for use in emergencies and tominimize overall time and costs. This wash process step ends when thefixed volume of isotonic solution is consumed.

The next process step is an additional wash with the same parameters,but using the red cell storage solution from the corresponding bag 5326.This process step continues until about 150 to 250 mL of the red cellstorage solution is consumed. Then the recirculation bag 5321 is emptiedvia the blood 5303 and RBC 5304 pumps through the CFC 5391 disk and intothe deglycerolized RBC bag 5322. The CFC 5391 disk removes additionalwaste fluid.

The last process step is to purge the recirculation bag 5321 and CFC5391 by pumping additional red cell storage solution into therecirculation bag 5321, into the CFC 5391 and into the deglycerolizedRBC bag 5322. The CFC 5391 remains filled with the red cell storagesolution at the end of the process (about 40 to 60 mL of volume). Thehematocrit in the deglycerolized RBC bag is about 50% to 60%.

The only difference between the processes illustratively depicted inFIGS. 53 and 54 is that the process depicted in FIG. 54 does not use anRBC pump, but instead uses a plasma pump 5404. The flow rate of RBCs outof the CFC 5491 is then determined by the difference between the CFC5491 inlet blood flow and the CFC 5491 outlet plasma flow. The RBC flowrate is therefore calculated and used in the same manner as the pumpedRBC flow rate to control the red cell-plasma interface within the CFC5491 disk and to calculate CFC inlet (and recirculation bag 5421)hematocrit.

The process illustratively depicted in FIG. 55 is also similar in manyrespects to those depicted in FIGS. 53 and 54. The process of FIG. 55differs in that it performs the mixing of two solutions to replace asingle isotonic (e.g., 12% NaCl) solution. This permits the osmolality(e.g., % saline) to be varied during the first two process steps; theaddition of a hypertonic solution to RBCs as they are transferred fromthe thawed glycerolized RBC bag 5523 to the recirculation bag 5521; andthe addition of a hypertonic solution to RBCs in the recirculation bag5521. Thus, the hypertonicity can be varied during these two processsteps to achieve optimal values and results. This may be accomplished byusing the solution pumps 5501, 5502 to vary the ratio of, for example,the hypertonic solution and isotonic solutions. This can achieve a slow,controlled reduction in wash solution hypertonicity in order to maintainshrunken RBCs during the wash process or achieve a slow rate of sizeincrease. Maintaining the RBCs in a substantially smaller, shrunkenstate during the wash may achieve several benefits: the glycerol withinthe RBC is more effectively removed by keeping a substantial osmoticgradient on the RBC and minimizing cell volume; the surface area tovolume ratio of the cell is increased to improve diffusion rate ofglycerol out of the cell and wash solution into it; and a reduced RBCvolume during the wash decreases hemolysis by preventing membrane damageto some fraction of RBCs that swell excessively during an isotonicsolution wash. To accomplish this, the configuration of the system inFIG. 55 includes two solution pumps 5501, 5502, rather than one solutionpump and one thawed RBC pump, as described with respect to theembodiments of the present invention depicted in FIGS. 53 and 54. Theother steps of the process illustratively depicted in FIG. 55 aresubstantially identical to those depicted in FIGS. 53 and 54.

The process illustratively depicted in FIGS. 56–58 is also similar inmany respects to those depicted in FIGS. 53 and 54. One difference isthat only two solutions are used in these embodiments, and each solutionflow rate and volume is controlled by its own pump.

The process illustratively depicted in FIG. 56 is almost identical tothat depicted in FIG. 53, except for the use of two independently pumpedsolutions contained in solution bags 5624, 5625. The RBC pump 5604transfers RBCs from the thawed deglycerolized RBC bag 5623 to therecirculation bag 5621; there is no separate thawed RBC pump.

The process illustratively depicted in FIG. 57 is almost identical tothat depicted in FIG. 54, except for the use of two independently pumpedsolutions contained in solution bags 5724, 5725. Another difference isthe pumping of the thawed glycerolized RBCs into the recirculation bag5721 using the blood pump 5703. The initial solution quantity is addeddirectly to the recirculation bag 5721 at a desired ratio to RBC flowrate. No static mixer is used.

The process illustratively depicted in FIG. 58 is similar to thatdepicted in FIG. 56. The differences are the gravity drainage of thawedglycerolized RBCs directly into the recirculation bag 5822 and that theinitial addition of solution is made directly into the recirculation bag5822.

Example 3 Alternative Solutions for Use in Deglycerolization Processes

The current storage solutions generally contain both glucose andelectrolytes such as sodium phosphate, sodium citrate and sodiumchloride. They are prepared at pH 5.7 or thereabouts since autoclavingto sterilize the solutions causes caramelization of the glucose whenboth glucose and salts are present at a pH much above 6.2. The principalrequirements for storage of RBCs after deglycerolization are hemolysisless than 1% and survival of transfused RBCs above 75% after 24 hours inhuman volunteers.

In order to obtain good refrigerated cell storage, the cells must beable to maintain metabolic processes. The presence of certainmetabolites, such as glucose, phosphate and adenine has been shown toachieve this, but for maximum benefit, the pH should be in thephysiological range of 7.0 or higher. Alkaline pH is not currently usedin RBC storage solutions because of the obstacle of sterilization byheat, which at high pH caramelizes the glucose used in storage solution.

The present invention provides one answer to this problem, by providingan alkaline pH wash solution in two bags; one containing the glucose(e.g., hypertonic glucose in the range of 30% to 60%), and the othercontaining the electrolytes (e.g., an isotonic solution containingsodium phosphate and adenine plus any other solutes such as sodiumcitrate or NaCl necessary to provide the desired osmolality withoutexceeding concentrations unacceptable for transfusion). These may becombined at the time of use by the systems of various embodiments of thepresent invention. The pH of the electrolyte solution is basic (e.g.,between about 7.0 and 9.0). Although entirely practical, this mayrequire another solution bag in addition to the hypertonic solution, thewash solution and the additive.

In practice, the hypertonic solution is used “full strength” for theinitial hypertonic dilution. The subsequent wash is created by mixingthe two solutions to produce a wash solution of either a fixedosmolality or a series of different osmolalities or a continuallychanging osmolality in order to optimize the efficiency of the washprocess. At the end of the wash, the wash solution contains theconstituents present in the two solutions at concentrations andosmolality suitable to serve as a storage solution during subsequentrefrigerated storage.

The goal of these approaches is to elevate the pH of the RBCs duringboth wash and post-wash storage, and to enable a more effective controlof osmolality during the wash process. These approaches shorten thedeglycerolization process; reduce hemolysis; permit longer refrigeratedstorage of deglycerolized RBCs; and, in some cases, may decrease thenumber and total volume of solutions needed.

Example 4 Intra-Operative Autotransfusion System

Use of the system of the present invention for intra-operativeautotransfusion provides significant advantages over conventionalautotransfusion systems, due, in large part, to the use of the CFC.Continuous flow centrifugation permits all fluid flow rates (e.g.,blood, waste, saline) to be directly controlled. This results in theability of the system of the present invention to respond immediately tochanges in inlet hematocrit and to maintain a particular waste removalefficiency with an optimized setting of fluid flow rates as determinedby the logic algorithm implemented by the microprocessor. The outlethematocrit is maintained always at the desired level (i.e., about 50% to55%), although this may be altered if medically desirable. Theperformance of a continuous flow system is not dependent on the quantityof blood in the reservoir to be processed. The current batch-processingcentrifuge bowls process blood differently for a full bowl than for apartially-full bowl. There is frequently a partially-full bowl processedwhen the final amount of blood in the reservoir is processed. Thecontrol afforded by continuous flow centrifugation permits the entireprocess to be made automatic, from sensing the presence of blood in thereservoir to controlling fluid flow rates to achieve a fixed outputblood hematocrit and a selected level of waste removal at any inlethematocrit. The continuous flow process is also inherently faster thanbatch processing.

The CFC has a relatively small internal blood volume and, consequently,a much smaller size than a conventional centrifuge bowl. This reducesthe amount of disposable plastic and associated cost. It also reducesthe mass of plastic and fluid subjected to high centrifugal forces;decreasing both the probability and magnitude of centrifuge structuralfailures.

An autotransfusion system 5900 utilizing the CFC 5991 of the presentinvention is illustratively depicted in FIG. 59. The system 5900includes a recirculation bag 5921 with a blood filter, connected to afiltered blood reservoir 5929 with a level detector 5998, and a bag forwashed RBCs 5922. A saline bag 5923 is additionally included in thesystem 5900. The bag of washed RBCs 5922 is connected to the system 5900via a Luer lock fitting 5999, and the saline bag 5923 and filtered bloodreservoir 5929 are connected with standard spikes 5962, 5961. A manualclamp 5965 is used when the washed RBC bag 5922 is disconnected from thesystem 5900. A mixer or shaker apparatus 5993 is included, tocontinually mix the contents of the recirculation bag 5921. A wasteproduct bag 5924 is additionally included in the system 5900, along witha free plasma hemoglobin sensor 5981. A laminar flow element 5997 isincluded, as well.

A CFC 5991 is included, as described in greater detail above. In thisembodiment of the present invention, the CFC 5991 separates washed RBCsfrom a waste product; thereby preparing the RBCs for reintroduction(i.e., transfusion) into a patient. An optical detector 5992 is includedwith the CFC 5991 to monitor the operation of the CFC 5991, as describedabove.

A saline pump 5901, filtered blood pump 5902, RBC pump 5903 andrecirculation pump 5904 are included to pump the various fluids throughthe system 5900. Pressure measurement devices 5911, 5912, 5913, 5914 areincluded to monitor the flow of the various fluids through the tubing,and ultrasonic air sensors 5931, 5932 are further included to monitorthe flow of air through the tubing (e.g., to determine when the fluidcontents of a particular bag have been evacuated). A microprocessor orother, similar electronic device (not shown) collects the informationfrom the pressure measurement devices 5911, 5912, 5913, 5914, ultrasonicair sensors 5931, 5932, free plasma hemoglobin sensor 5981 and opticaldetector 5992, and controls the valves 5941, 5942, 5943, pumps 5901,5902, 5903, 5904 and CFC 5991, accordingly, to implement theautotransfusion process. Additionally, the bags and various othercomponents of the system are connected to one another by tubing incommunication with a cassette (not shown) designed specifically for theoperation of this embodiment of the present invention, as discussed ingreater detail above.

A separate disposable (e.g., standard suction wand, suction tubing and ablood or cardiotomy reservoir) is used to collect blood from thesurgical field in any surgical procedure (e.g., cardiac, vascular,orthopedic and the like) where significant blood loss may occur. Theblood reservoir 5929 may contain a blood filter and a defoamer. Blood ispumped from the blood reservoir 5929 to the CFC 5991 through a laminarflow tube 5997. A saline pump 5901 adds saline to wash the RBCs in theCFC 5991. A waste pump (not shown) may be included to remove waste fluidfrom the CFC 5991 to a waste bag. Output (i.e., washed) blood flows tothe blood bag 5922. The presence of blood in the reservoir 5929 issensed by starting the blood pump 5902. If blood is in the reservoir5929, the blood 5902, saline 5901, and RBC pumps 5903 continue tooperate until the reservoir is empty 5929. Air from the reservoir 5929is detected by a standard ultrasonic air bubble detector 5932. Thissignal is used to turn off all pumps. The blood pump 5902 reverse-flowsa few milliliters to push air out of the blood line back into thereservoir 5929. Then, the pumps start up in 15 seconds. If air isdetected, the blood pump 5902 pumps the air back into the reservoir 5929and the pumps stop. This process is repeated until blood is collected inthe reservoir 5929, and pump operation resumes until the reservoir 5929is empty.

Pressures are measured at the entrance 5911 and exit 5912 of the laminarflow tube 5997. The pressure drop across this tube 5997 is proportionalto blood flow rate and to blood viscosity, which is a direct function ofhematocrit. Viscosity is also temperature-dependent and the localtemperature is measured and used in the logic algorithm to moreaccurately correlate viscosity with hematocrit. The fluid flow rates ofthe blood 5902, saline 5901 and RBC pumps 5903 are controlled by thealgorithm to achieve the desired outlet blood hematocrit and theappropriate waste removal efficiency at any measured inlet bloodhematocrit. Pressure is measured between the RBC pump 5903 and thewashed RBC bag 5922 to alert the operator when the blood bag 5922 isfull and should be replaced with another bag. Blood can flow from thisblood bag 5922 directly to the patient while blood is being processed,or the blood bag 5922 can be removed and hung nearer the patient forgravity or pressure infusion. The recirculation wash process may be thesame as that described in Example 2, above.

Example 5 Process for the Production of Leukoreduced Platelets fromPooled Buffy Coats

The system of the present invention may be used to pool buffy coats andseparate platelet and white cell products from them. The plateletproduct may be leukoreduced. The objectives for this process are: totake multiple buffy coats produced, e.g., in an alternate embodiment ofthe present invention, and to combine or pool these buffy coats; toprovide a single therapeutic dose of leukoreduced platelet product andan optional white cell product from pooled buffy coats; to achieve ahigh degree of and possibly adequate leukoreduction by centrifugalseparation (e.g., with a small, low-cost leukofilter optionally added,if necessary to ensure consistent leukoreduction); to remove RBCs fromthe buffy coat by centrifugation; to achieve significant time and costadvantages by automating a process that is now only performed manually;and to eliminate the expensive leukofilter from this process entirely,or use a much smaller and less expensive one.

A system 6100 for preparing leukoreduced platelets from pooled buffycoats is illustratively depicted in FIG. 60. The system includes atleast one buffy coat bag 6121–6125; each connected to the system via asterile dock 6171–6175, respectively. A Platelet Additive Solution (PAS)bag 6126 is also included, along with a bacterial filter 6151 tomaintain sterility of the system 6100. An air vent filter 6152 isincluded, as well as a leukofilter 6153. A platelet product bag 6127 andwhite cell product 6128 bag collect the various blood products separatedby continuous flow centrifugation.

A CFC 6191 is included, as described in greater detail above. In thisembodiment of the present invention, the CFC 6191 separates the plateletproduct from the white cell product portion of the pooled buffy coats.An optical detector (not shown) is included with the CFC 6191 to monitorthe operation of the CFC 6191, as described above.

A PAS pump 6101, cell pump 6102 and a platelet pump 6103 are included topump the various fluids through the system 6100. Pressure measurementdevices 6111, 6112 are included to monitor the flow of the variousfluids through the tubing, and an ultrasonic air sensor 6131 is furtherincluded to monitor the flow of air through the tubing (e.g., todetermine when the fluid contents of a particular bag have beenevacuated). A microprocessor or other, similar electronic device (notshown) collects the information from the pressure measurement devices6111, 6112, ultrasonic air sensor 6131 and optical detector (not shown),and controls the valves 6141–6149, pumps 6101, 6102, 6103 and CFC 6191,accordingly, to implement the process of this embodiment of theinvention. Additionally, the bags and various other components of thesystem are connected to one another by tubing in communication with acassette (not shown) designed specifically for the operation of thisembodiment of the present invention, as discussed in greater detailabove.

In operation, buffy coat bags 6121–6125 (up to about 5) are sterilelydocked (e.g., via a Luer fitting 6171–6175, respectively) to thedisposable set and a bag of PAS 6126 is attached (e.g., via standardspike or other connector) to the set. Solution sterility is maintainedwith a bacterial filter 6151. This disposable set cassette is insertedinto the console, the door is closed, and the bags are hung on hangerson the console sides. The bar code on the cassette is read by theconsole to implement the leukoreduction from pooled buffy coat process.The user pushes the “Start” button and the complete process isthereafter automatic. At the end of the process, the platelet 6127 andwhite cell 6128 product bags are sealed off and removed from the set.The disposable set is then discarded.

The process includes the following: provide platelet storage solution toeach buffy coat bag (in addition to the approximately 20 mL of plasma ineach bag from a blood separation process); pump buffy coat into whitecells and any contaminating RBCs at the periphery, platelets at asmaller radius and solution at radii smaller than the platelet layer;and remove white and red cells from the CFC 6191 to a white cell productbag 6128 and simultaneously pump platelets and PAS through a leukofilter6153 to a platelet product bag 6127. The process also includes: rinsingeach buffy coat bag 6121–6125 with PAS after the bag is emptied;emptying the bags 6121–6125 again; and centrifuging the fluid toseparate and remove to product bags 6127, 6128 the residual platelets,leukocytes and RBCs. The process may additionally include a purge of theleukofilter 6153 with PAS to remove a percentage of trapped platelets.

It will be readily apparent to one of skill in the art that the variousprocess steps and methods of the above-described embodiments of thepresent invention can be combined to make additional processalternatives without departing from the main concepts of the invention.It will be evident that other processes could be implemented using thebasic console and cassette design. The presently disclosed embodimentsare therefore to be considered in all respects as illustrative and notrestrictive, the scope of the invention being indicated by the appendedclaims, rather than the foregoing description, and all changes whichcome within the meaning and range of equivalency of the claims aretherefore intended to be embraced therein.

1. A system for separating blood components from a buffy coat,comprising: at least one buffy coat bag to contain at least one unit ofbuffy coat, each of said at least one buffy coat bag in fluidcommunication with an input tubing by a sterile dock; one buffy coatvalve for each of said at least one buffy coat bag, each of said buffycoat valves configured on said input tubing segment so as toindividually control the flow of buffy coat from one of said at leastone buffy coat bag; a continuous flow centrifuge (“CFC”) to separateplatelet products from white cell products in said buffy coat, said CFCin fluid communication with said at least one buffy coat bag said inputtubing, said input tubing terminating at said CFC; a platelet additivesolution (“PAS”) bag to contain PAS, said PAS bag in fluid communicationwith said input tubing by a PAS tubing segment, said PAS tubing segmentterminating at a first end at said PAS bag, and terminating at itssecond end at a PAS junction located between all of said at least onebuffy coat valve and said CFC; a PAS pump to pump said PAS from said PASbag, said PAS pump configured on said PAS tubing segment; a bacterialfilter to maintain sterility of said system, said bacterial filterconfigured on said PAS tubing segment between said PAS pump and said PASbag; a cell pump to pump said PAS and said buffy coat to said CFC, saidcell pump configured on said input tubing between said PAS junction andsaid CFC; a platelet product bag to contain platelet product separatedfrom buffy coat by said CFC, said platelet product bag in fluidcommunication with said CFC by a platelet tubing segment; a plateletpump to pump said platelet product from said CFC to said plateletproduct bag, said platelet pump configured on said platelet tubingsegment; a white cell product bag to contain white cell productseparated from buffy coat by said CFC, said white cell product bag influid communication with said CFC by a white cell tubing segment; aplatelet valve to control the flow of said platelet product from saidCFC, said platelet valve configured on said platelet tubing segmentbetween said CFC and said platelet pump; a white cell valve to controlthe flow of said white cell product from said CFC, said white cell valveconfigured on said white cell tubing segment between said CFC and saidwhite cell product bag; a supplemental valve to control a flow of fluidbetween said platelet tubing segment and said white cell tubing segment,said supplemental valve configured on a supplemental tubing segment,said supplemental tubing segment in fluid communication with saidplatelet tubing segment at a platelet junction on said platelet tubingsegment between said platelet valve and said platelet pump, and saidsupplemental tubing segment in fluid communication with said white celltubing segment at a white cell junction on said white cell tubingsegment between said CFC and said white cell valve; and a cassettethrough which said input tubing, PAS tubing segment, platelet tubingsegment, white cell tubing segment and supplemental tubing segment pass.2. The system of claim 1, further comprising: a first pressuremeasurement device to detect the flow of platelet product through saidplatelet tubing segment, said first pressure measurement deviceconfigured along said platelet tubing segment between said platelet pumpand said platelet product bag; a second pressure measurement device todetect the flow of fluid into said CFC through said input tubing, saidsecond pressure measurement device configured along said input tubingbetween said cell pump and said CFC; and an ultrasonic sensor to detectair in said input tubing, said ultrasonic sensor configured along saidinput tubing between all of said at least one buffy coat valve and saidPAS junction.
 3. The system of claim 1, further comprising a leukofilterto aid in leukoreduction, said leukofilter configured on said platelettubing segment between said first pressure measurement device and saidplatelet product bag.
 4. The system of claim 1, further comprising: anair vent filter in communication with said PAS tubing segment by an airvent filter tubing segment, said air vent filter tubing segmentconnecting to said PAS tubing segment between said PAS pump and said PASjunction; and an air vent filter valve configured on said air ventfilter tubing segment.
 5. The system of claim 1, further including aconsole that houses said cassette.
 6. A method of separating bloodcomponents from a buffy coat, comprising: providing a system forseparating blood components from a buffy coat, including at least onebuffy coat bag containing at least one buffy coat, each of said at leastone buffy coat bag in fluid communication with an input tubing, aplatelet additive solution (“PAS”) bag containing PAS, said PAS bag influid communication with said input tubing by a PAS tubing segment, saidtubing segment terminating at a first end at said PAS bag, andterminating at its second end at a PAS junction, a continuous flowcentrifuge (“CFC”) adapted to separate a platelet product and a whitecell product from a buffy coat, said CFC in fluid communication withsaid at least one buffy coat bag, said PAS bag, a platelet product bagand a white cell product bag by way of tubing, wherein said PAS junctionis located between all of said at least one buffy coat bag and said CFC,a cassette through which said tubing passes, and a cell pump to pumpsaid PAS and said buffy coat to said CFC, said cell pump configured onsaid input tubing between said PAS junction and said CFC; configuringsaid system system with a console including electronic and mechanicalcomponents to operate said system; and operating said system to separateblood components from a buffy coat.